A systemic functional analysis of multisemiotic biology texts 5

In what follows I discuss the page layout and colour schemes of the texts Section 5.1, present the frequencies of the categories of visual displays that occur in the texts Section 5.2 an

CHAPTER FIVE MULTIMODAL CONSTRUCTION OF BIOLOGICAL KNOWLEDGE

In this chapter I present the results of the analysis of the visual selections and how the visual text relates to and interacts with the linguistic text By visual text I refer to the semiotic resources deployed in the print media biology textbook that depend on the transmission and reflection of light on a treated surface (rather than the transmission of sound in the air) to make meaning, including the typographical features of the writing system of the English language However, the focus of this chapter is on the visual displays such as schematic drawings, tables, statistical graphs and micrographs This chapter takes as points of departure the discussion of the frameworks for the analysis

of the visual display and seeks to illustrate how meanings are made in the texts using a variety of resources Thus it complements in a significant measure what is presented

in Chapter Four, which is the analysis of meanings made through the linguistic semiotic code It will be seen that biologists do not rely on language alone to make meaning and that visual displays are an important resource for meaning-making In what follows I discuss the page layout and colour schemes of the texts (Section 5.1), present the frequencies of the categories of visual displays that occur in the texts (Section 5.2) and then analyze one visual display of each main category (Section 5.3)

I conclude this chapter with a brief summary (Section 5.4)

5.1 Page Layout and Colour Schemes in the Texts

Before conducting detailed analysis of selected visual displays in the texts we need to consider three issues that affect not only any one visual display but also almost all meaning-making in the texts, issues that enable and constrain meaning-making in the first place First, how big is the page and how is it designed in a way that provides a textual space where meanings are made? Second, how is colour deployed to make meaning? And thirdly how is the reader expected to move his or her attention from one semiotic mode to another in a multisemiotic text, and within one semiotic from one part to another? Since the last issue, i.e the reading path, has been dealt with in Section 3.2.3 above, I discuss the first two questions below

First, a page is a textual as well as a physical unit At first glance, a page is a physical object on the surface of which words and pictures are printed: we can touch it, turn it and tear it from the book Physically speaking, then, the pages of all three texts adopt a size close to the standard A-4 size paper, measuring about 10.8 × 8.3 inches The selection of such a size can be seen as a response to the increasing number of visual images in the texts, as well as to the size of the school bag, the desk and the hand of a university student in his or her late teens A bigger book makes it easy to arrange the images and the words and a pocket size edition of these biology texts would be hard to imagine The page size is among the first factors affecting the page design At the same time, a page is also a small-scale multimodal meaning-making unit (Baldry 2000b: 41-42): it has internal design, page layout, that organizes its various textual elements Kress and van Leeuwen (1996: 183) approached this issue in terms of the systems of INFORMATION VALUE, SALIENCE and FRAMING (see Section 3.1.2.2 above) What is equally fundamental is the column grid of the page

In Texts 1 and 2, a normal page with the exception of end-of-chapter “Essential Concepts” pages and “Questions” pages, which are in double column, and “Key Terms”, which are listed in four-column tables in Text 1, and end-of-chapter

“Summary”, “Exercises” and text boxes, which are in double column, and “Key words”, which are listed in three columns in Text 2, is split into main text (the body) and text margin (see Figures 1.1 and 1.2 above for sample pages) Physically speaking, the width of the margin is around half of the body of the text, that is, two-thirds of the left-right page is devoted to the body of the text and one-third to the margin (see Figure 5.1) There is a gutter of approximately 1 cm to set apart the body and the margin

body

Figure 5.1 Demarcation of the page in Texts 1 and 2

The demarcation of main text and text margin is intended to serve a purpose in the texts The major running text appears only in the body of the page, while the caption text, visual display and in-chapter questions (in Text 1) are printed in the text margin That is, the text margin provides a place where questions are asked about what has been talked about in the body of the text or explanatory texts (caption) are provided for the visual display in the body of the text From this we see that the page has one part that is the chief information provider and another part that serves a subordinate role: as a question, explanation or facilitator of the main text1

The page layout of Text 3 is different Except for the large visual displays such

as Figure 23.30 that extend from the left to the right of the page, the page contains two

equal columns, with a gutter of about 1cm to separate the two portions (see Figure 1.3 for a sample page)

Another aspect of the page as a textual unit is that the main text and the figures they refer to are laid out with a page or a two-page spread as a unit As S Gibbs, the

managing editor of ECB (personal communication, February 8, 2001), notes,

In “laying out” book pages we always try to ensure that figures are in

close proximity to where they are discussed in the text This means that

the reader is not distracted by having to turn pages in order to find the

relevant figure

The second issue that affects meaning making in the texts is concerned with the use of colour, or the colour scheme, i.e the principled selection of a number of colours out of “systems of colour” (Kress and van Leeuwen 2002: 366) Human vision, and therefore visual semiosis, depends on, or is realized through colour Without light or colour we do not see anything The essential issue is the colour scheme of the textbook, black and white or full colour Texts 1 and 2 are full colour while Text 3 is largely black and white

In Table 3.2 “Functions and systems in schematic drawing” above, I identify

“colour” as a semiotic resource operating across all three metafunctions First, in a schematic drawing, colour can be used to represent the original colour of the natural world, for example, the green to represent the colour of the leaves Thus colour may

function as an experiential resource In this respect, the colour in the drawing shows

directly this aspect of the original object to a very high fidelity with or without the aid

of natural language Colour can also be used to represent abstract entities, such as the blue of the uniform to signal that the wearer is a policeman or policewoman Second, where the colour in the drawing is added, extraneous of the original object, the colour may serve to engage the viewer Thibault (2001: 317) notes that “[full] colour is

usually the unmarked choice in modern science textbooks for school pupils” and that

“the reasons are mainly interpersonal” (2001: 317) The textbook authors / publishers engage and interact with the student readers by inviting them to experience the colourful (though not necessarily faithful) materiality of the subject matter Reading textbooks thus becomes a sensory, physiological experience, as well as an intellectual one Thirdly, colour in the drawings may also serve to link the visual elements, “to provide cohesion and coherence” (Kress and van Leeuwen 2001: 58) In Texts 1 and

2, for instance, green, coupled with larger font size and initial capitals, is used to signal the headings and in Text 2 boxed essays are shaded with light green Citing the example of the use of colour in maps, Tufte (1990: 81; original emphasis) summarizes

“the fundamental uses of color in information design” as follows: “to label (color as noun), to measure (color as quantity), to represent or imitate reality (color as representation), and to enliven or decorate (color as beauty)” Kress and van Leeuwen

(2002: 350) further argue that because colour has been culturally shaped to construct all three metafunctions, it may be considered as “a semiotic mode in its own right, along with language, image, music, etc”

5.2 Categories of Visual Displays in the Texts

The types of visual displays that are selected in the texts and the frequency of each type are summarized in Table 5.1 As seen here, the three texts show considerable variation in the types and frequencies of visual display For instance, structural formulas of molecules2 and equations of reactions occur in Text 2 only A structural formula describes how the various atoms in a molecule are bonded together and an

Text 1 Text 2 Text 3 Types

Table 5.1 Types of visual display

equation describes what reactants participate in the reaction under certain circumstances and what products result They are thus well suited for the biochemistry text In Texts 1 and 3, on the other hand, schematic drawings are most frequent, followed by micrographs, i.e photographs taken through a microscope

The three texts also differ in the extent of integration between the linguistic text and images Whereas in Texts 1 and 3 the visual images are separated from the linguistic texts but are referred to in the latter, for example by “(see Figure 17-6)” (in Text 1), in Text 2 the structural formulas and equations are very often integrated with the linguistic text so that no separate title or caption is felt necessary for the formulas

and equations: they have in these cases become part of the running text In Text 2, only when the formulas and equations become extremely complex do they occupy a separate section on the page (e.g Figure 10.1 of Text 2)

In addition, the schematic drawings and the micrographs in Texts 1 and 3 occur

in two forms, either alone or in “split-screen” format, that is, one or more micrographs are juxtaposed with their simplified schematic drawings, side by side within one figure

or occasionally in two adjacent figures But as will be seen in the analysis of Figure 17-10 in Text 1 below, the micrograph and its schematic drawing counterpart in a split-screen format are not equivalent Whereas the former is believed to be a trace of nature, the latter is a pedagogic reconstruction of the trace Overall, it seems that the schematic drawings are intended to contribute more to the construction of biological knowledge in the textbooks than the micrographs, which serve merely as the

“guarantee” of the reality (Bastide 1990: 213) and “a guarantee of objectivity” (Barthes 1977: 44) These guarantees form one of the bases for the claims made in the linguistic and visual (i.e schematic drawing) text It also seems to follow that the drawings need to be studied carefully while a glance is sufficient for the micrographs

On the other hand, the distributional features of the visual displays described above, like those of the verbal text that they accompany, are realizations of particular contextual configurations; the distribution and the types of visual displays may well differ if other texts are analyzed

5.3 Textual Analysis of Some Figures

In this section3 I analyze a schematic drawing (Section 5.3.1), a micrograph (Section 5.3.2), a split-screen format of a drawing and a micrograph (Section 5.3.3), a statistical

graph (Section 5.3.4), a scientific table (Section 5.3.5), and the structural formula of a molecule (Section 5.3.6) The analyses are presented in decreasing detail so that only the prominent and new features are discussed in the latter analyses

5.3.1 A Schematic Drawing: Figure 17-3 of Text 1

Figure 17-3 (ECB: 549), together with the relevant verbal text, is reproduced in Figure

The reading path within Figure 17-3 is marked in Figure 5.2 by the blue italicised Roman letters A to G As is clear from Figure 5.2, the reading path is not linear, from left to right, from top to bottom, but is determined Ideationally by what is

in focus in the running text (the M phase of the cell cycle), and Interpersonally by the visual means of directing the reader’s attention (for example, the bright yellow

Figure 5.2 Reading path for Figure 17-3

Shading and Capitalization of MITOSIS and CYTOKINESIS and light green Shading

of M phase and the large square bracket embracing MITOSIS and CYTOKINESIS) This is, in verbal and common parlance, equivalent to saying “Hey, look at what is highlighted first!” Indeed, in this part of the reading, Steps C and D are all an experienced reader needs to attend to The highlighting devices such as arrows are equivalent to a lecturer’s cursor in an actual classroom, where he or she, while talking

to the students, points to relevant parts of the figures Although in viewing Figure 17-3 one’s gaze, especially that of a novice, may work from Step G down to Step D due to the Interpersonal impact of the downward-pointing arrows and the reading habit of a normal reader, it is nonetheless arguable that the reading path suggested above is most economical for the experienced reader, that is, one that has followed the textual explication up to this point

At the rank of Work, Interpersonally, this figure thus employs an array of visual means to emphasize various parts of the cell structure and stages of cell division Ideationally, the figure is designed to tell a story about what happens in a cell cycle, in particular the M phase of the cell cycle The Ideational meanings include: (a) material processes realized by changes in the shapes at different stages, the arrows and the nominal groups in the linguistic text, (b) intensive identifying processes realized by the labels, leaders and the pictorial elements, and, in the absence of leaders by the labels, the spatial proximity between the pictorial element and the labels, and the pictorial elements, and (c) possessive identifying relational process realized by the labels, the square bracket, the pictorial elements and the linguistic text The overriding experiential content seems to be concerned with material processes, although the intensive and possessive relational processes contribute significantly to the construction of biological knowledge And Textually, the drawing is not isolated from

the other parts of the text It is related to the main text and the caption and is placed in

a specific position on the page, that is, in the text margin The drawing is vertically positioned, with the Arrows connecting one stage with another Other resources employed for the Textual meaning include Geometry (e.g circles), Colour Contrast or Similarity, Labelling (with or without leaders), and Framing In what follows, I analyse selected steps in terms of the Interpersonal (Modal) meaning, Ideational (Representational) meaning and Textual (Compositional) meaning, by reference to the functions and systems chart in Table 3.2

Step A The Title

Distinctive typographical features, such as the boldface of the title and the greenness of the figure’s serial number, function to attract the reader’s attention and thus attach more importance to this linguistic message The title is also the only explicit link to the main text; it is the reader’s entrance to the pictorial world of the figure It is designed to be read first and taken as the point of departure for what is to come next

The title is a nominal group and apparently does not select an Interpersonal stance at the rank of clause in terms of SPEECH FUNCTIONS (Offer or Demand) and MODALITY and MODULATION (Halliday 1994) This is a nominal group whose function is termed by Halliday (1994: 96) as “Absolute” in that it “could be either Subject or Complement in an agnate major clause” Indeed all the linguistic components except the caption in Figure 17-3 are “[u]nattached nominals” (1994: 395) which function in this way But such nominal groups are nonetheless far from being free from any Interpersonal meaning As for this title, the nominal group presents the Process of a cell dividing as a Thing, which is objective, absolute, visible and concrete

Such a high level of certainty about the state of affairs is attainable through nominal groups or grammatical metaphor in the form of nominalisation (Halliday 1993a; 1998)

In other words, distillation of phenomena into entity or transformation of clausal grammar to nominalised form means that the reader is not in a position to doubt the existence of a phenomenon, but is led to believe in its absolute, timeless and unconditional existence

Ideationally, being a nominal group, the title serves to identify, and is thus equivalent to an intensive identifying clause (Halliday 1994: 119-120), for example

“This is the drawing of the M phase of the cell cycle” It is important to note that the nominal group identifies not only through language but also by its spatial proximity to the schematic drawing By itself this nominal group points to a nominalised process, the M phase of the cell cycle Thus a sequence of dramatic events, where one cell splits into two, has been transformed into a Thing which has consequently been deprived of all the original vigour, liveliness and particularities

Step C MITOSIS

This step can be broken into three sub-stages: Step C-1 the word “MITOSIS”, Step C-2 the arrow and Step C-3 the circle and the two overlapping circles which contain the semiotic depiction of the cell

Step C-1 the word Typographical features such as the largest font Size, Capitalization, and bright yellow Shading serve to attract the reader’s attention, as if saying that MITOSIS and the drawings it refers to are what the reader needs to pay special attention to

Step C-2 the arrow Interpersonally, the single-headed arrow is a Command; it demands that the reader look in the direction of the arrow, in this case, from top to bottom of the page Here, the Command effect is strengthened by the particular darkness and thickness of the arrow

Ideationally, the arrow serves to signify the process and direction of movement, change or progression, or the numerous intermediate phases between the circle above and the circles below In terms of Peirce’s (1985: 9-12) trichotomy of signs into an index, an icon or a symbol4, the arrow is a highly stylised icon That is, the arrow proper does not exist in the actual world in the process of cell division; the designers

have added it to the depiction Besides, the direction of the arrow in the physical

sense, i.e from top to bottom, is iconic of progression in time

Step C-3 the circles Inside the circle (second from top), highlighting devices such as the Colouring of the two pairs of lines and pink Shading serve to draw attention to the essential defining features of a cell at this stage The blank space (Omission) between the outer ring of the circle and the pink shaded central area is, in reality, just as occupied as other parts of the cell This distortion functions as yet another means of highlighting the two pairs of lines The outermost black circle and the adjacent blank space inward (Omission) surround the central pink shaded area, serving as a Framing to give weight to what is highlighted in the centre The Contrast

of colour between black, red, pink and white serves the same highlighting purpose; at work here is the colour scheme employed: bright red and dark black against a white and light pink background so that the former stand out

Ideationally, the circle is drawn to represent a snapshot of a particular stage in cell division It focuses on the separation of the two pairs of chromosomes, omitting the changes taking place in the cytoplasm The Ideational meaning is realized by the

changes in shapes and contents of the pink-shaded area and also by the Diagonal orientations of the two pairs of lines representing chromosomes We need to note that this circle is not an obvious icon (Peirce 1985) The two pairs of lines inside and the circular shapes do somewhat resemble some types of cell components, hence they are iconic But the colours, the circle and the blank space testify to the symbolic nature of the iconic sign For instance, the colour of a particular cell component one sees in a micrograph is the result of dyeing technique However, what is shown in the micrograph is not necessarily reproduced in a schematic drawing; in a drawing further treatment is carried out to produce what appears in the final printed book In other words, what meets a reader’s eye in a schematic drawing is at least two steps away from what is really there: in terms of choice of colour and diagrammatic transformation

Textually, several devices contribute to the organisation of the text For instance, Colour Cohesion and Contrast enable the viewer to recognize similarity and difference in the Ideational meaning and Interpersonal meaning: the colours red, pink, black and white serve as a backdrop against which the Ideational and Interpersonal meanings are expressed Similarly, the Shapes of the components, i.e the lines, circles, and the Relative Position of the components also constitute a resource to organize the text Below I discuss in greater detail the role of Horizontals, Verticals and Diagonals in the Textual organization in the schematic drawing

The two pairs of lines in the first circle in Step C are positioned diagonally relative to the vertical-horizontal frame of the drawing The red pair resembles the contour of a hill or sea wave, each of which is perceived as the trace of drastic movement or thrust resulting from the physical or geographical forces such as the gravitational pull The axis of the black pair is approximately 30° anticlockwise to the

vertical axis of the drawing This tilt or obliqueness creates “directed tension” (Arnheim 1974: 424-428), or “energy and dynamism” (O’Toole 1994: 23; Thibault 1997: 315-322) We may note that whereas the shape of the red pair of lines remains roughly constant throughout the drawing, the black pair tilts most in Step C This well fits the Ideational theme of the step, which is concerned with drastic change in terms of chromosomes in the nucleus On the other hand, the Diagonal orientations of the two pairs of lines in the step also serve to connect this step with the preceding and following steps, thus contributing to the Textual organization or unity of the drawing

In other words, obliqueness in orientation of the lines is echoed or shared by all the steps in the drawing albeit to varying degrees It is true that in the laboratory cell biologists will know that the cells are undergoing some transformation however they are aligned relative to the mechanical stage of the microscope But when cells are

represented in micrographs and in particular in schematic drawings, that is, when they

are turned into lines, circles and so forth, to contribute to the Textual organization, “the canons of classical painting” (Bastide 1990: 199-200) are often respected One such canon is the deployment of oblique lines to represent “energy and dynamism” (O’Toole 1994: 23; Arnheim 1974: 424-428)

Step D CYTOKINESIS

Again, Step D can be broken into Step 1 the word, Step 2 the arrows and Step

D-3 the two circles (at the bottom of the figure) Below I analyze the arrows and the two circles

Step D-2 the arrows Interpersonally, the fork arrows serve to draw our attention to what the arrows point to, i.e the two circles What is distinct about these

arrows is that they point to two directions instead of one, as in previous arrows This means that the reader need pay attention to the two separated circles Ideationally, the fork arrows symbolize separation, one cell divided into two cells, or they represent the numerous intermediate stages between the completion of mitosis and the completion of cytokinesis And in terms of Compositional meaning, a short line and two short arrows are deployed to realize the Ideational and Interpersonal meanings

Step D-3 the two circles Interpersonally, one’s eye line is drawn to the two circles by the two directional arrows The two circles are quite large, designed to attract the reader’s attention The two smaller inner circles representing nucleuses are highlighted by the same devices as in the above circles The white space between the two large circles, quite unlike the empty space inside the circles, is the background of the image and indicates that the focus of attention now is on the fact that the two circles have moved apart Ideationally, if we compare the two smaller inner circles (standing for nucleuses) at this stage with those at the end of mitosis, i.e the contents

of the circles, we find they are identical; what has changed is that the two partially overlapping circles have now become two separate circles This means cytokinesis is mostly concerned with the separation of cytoplasm (signified by the white space between the outer and inner rings) so that each new cell gets its share of outer support materials The two large circles also mark the end of the M phase, hence also one typical cell cycle Textually, in addition to the textual resources employed earlier in the drawing, such as Colour Shading and Framing, Symmetry of the two circles (i.e their identity and symmetrical horizontal alignment) and the fork arrows brought forward from the previous phase also contribute to the Textual meaning

Step E The Caption

The caption has less visual salience through smaller font size, normal type (i.e not boldface) and shorter leading This suggests that the caption is to be read later in the reading sequence The lexicogrammatical features of the caption are discussed in the linguistic text analysis presented in Chapter 4 and thus not repeated here It is worth noting, however, that Ideationally the caption presents a possessive identifying relation and circumstantial identifying relation, realized respectively by the verbal groups

“consists of” and “followed by” This repeats the information presented in the main

text (for example in the clause “These two processes together constitute the M phase

of the cell cycle”) The caption, however, serves in particular to specify what the square bracket in Step B refers to, that is, it is a visual iconic expression of a possessive identifying relation Here we can appreciate that while the visual images

are important in biological texts they have to be given categorical meanings by

linguistic resources The value of the visuals in this figure is that, in addition to

representing or constructing the shapes of biological entities, they are a spatialization

or icon of the temporal flow of events and also aid to construct a taxonomy of biological terms (the relations between M phase, mitosis and cytokinesis) However, language has to specify the relations and their visual transformation (cf Barthes 1977: 38-41)

Step F Chromosome Replication

This step can be broken into two sub-stages: Step F-1 the words “chromosome replication” and Step F-2 the arrow

Step F-2 the arrow Compared to the others, this arrow is short, indicating less Prominence in the figure This arrow also leads the reader’s attention to the next visual representation Ideationally, this arrow denotes the process by which one pair of chromosomes duplicates into two pairs One needs to note, however, that the shortness

of this arrow misrepresents the length of the time period That is, replication in the S

phase takes much longer than the M phase A typical eucaryotic cell spends a fraction

of its cell cycle time in the M phase, and most of it in interphase, as noted in ECB,

page 549 For example, a mammalian cell of a 24-hour cell cycle requires only about one hour for the M phase to complete This misrepresentation of the temporal dimension functions to highlight the M phase of the cell cycle

Step G The Structure of the Cell

Step G is located at the top of the figure and an uninitiated reader may begin viewing the figure here as this step provides the background for what follows The labels in this step and the leaders functioning as the identifying processes disappear in the later depictions This means that once they have fulfilled their contextualising function, they are discarded and are no longer made visible Having previously established the

structure of the cell in ECB, the reader is now invited to study in detail the M phase

As argued above, the experienced reader reads Step A first and this step last or simply skips this step, as would perhaps a lecturer in the classroom This step can be read in two sub-stages: G-1 the circle and G-2 the labels

Step G-2 the labels Like “chromosome replication” in Step F, the words in Step G-2 are made least prominent by means of smaller font Size, no-Shading and no-Capitalization The leaders are also made insignificant by means of Length and

Weight Ideationally, they identify the major components of a cell, as if saying, for example, “This is the nucleus of the cell”

I now conclude the analysis of Figure 17-3 with a discussion of the ideational complementarity of language and visual images Stripped of the language, the visuals (circles and especially arrows) seem to tell a story and speak for themselves That is,

by viewing the visuals alone, we would get an impression of change or movement, but would have little idea of what the visual images are about: they either say too much in that there are too many possible interpretations one can make, or they say too little in that they do not give the reader a clear orientation Thus the language comes in to capture some moments in the cell cycle, i.e to condense and nominalise, define, categorize, theorize about, or anchor, what the visuals show, for instance, the change from this stage to that one is called mitosis In the words of Barthes (1977: 38-39; original emphasis)

all images are polysemous; they imply, under their signifiers, a ‘floating

chain’ of signifieds, … Hence in every society various techniques are

developed intended to fix the floating chain of signifieds in such a way

as to counter the terror of uncertain signs; the linguistic message is one

of these techniques

Stripped of the visuals, on the other hand, the caption text and the relevant main text make the relational meanings of intensive, circumstantial and possessive types (and later in the text material relations are to dominate), but the reader would never have any concrete idea of what a cell looks like, or how it changes its shape from one stage to another, or what colour each cell component may be, hence the need for

the visuals to show the shape, colour, and so forth This complementarity between

language and visual images arises from their different functionalities and limitations

Language, in essence, generalizes and categorizes, discarding the non-essential features, and is thus typologically straightforward but topologically ambiguous (Lemke 1998a: 87), while visuals are more or less effective for constructing topological meanings, sometimes at the expense of typological meanings

The co-deployment of both the visual and the language is absolutely essential for biology for two reasons (cf Section 3.2.1) First, much of what is captured under the microscope is natural shape, colour, and process that in a sense defy a linguistic version, or rather, natural language has not yet evolved to such a degree of accuracy as

to be of practical use to natural science, if it is the sole resource employed Take the example of shape The “shape” words in English include square, circle, rectangle, triangle, pentagon, and so on, hardly adequate for the description of the numerous shapes we find around ourselves If the situation requires an adequate description of such topological meanings, language may turn out to be inadequate and other semiotic

resources may be called for Not that natural language can never fully express the

topological meanings, but that other semiotic resources work much more efficiently

and accurately Visual display is one such resource It can show readily and exactly

what one sees, or perceives Secondly, the visual devices (e.g the square bracket, the leaders) that serve to identify, or establish links between the linguistically coded meaning (e.g mitosis) and what is visible under the microscope (e.g the change one observes in the laboratory) are symbolic in that in real life there do not exist such devices Rather, they are created by the textbook authors to mean in a specific way, to stand for and realize particular meanings By visualizing the possessive / intensive /

circumstantial identifying meanings the readers are able to perceive the relations

Obviously, that the possessive / intensive / circumstantial identifying meanings are

represented visually as a square and so forth does not mean that under the microscope

we can see them: they are the products of scientists’ conceptualization

5.3.2 A Micrograph: Figure 17-11 of Text 1

5.3.2.1 Types of Micrographs

Cells are small, transparent and mostly colourless; in their natural state they are not visible to human vision So the study of cells has depended on the development of instruments, especially microscopes, and on specimen preparation Since Robert Hooke (1635-1703) first observed cells with the help of a light microscope in 1665, microscopists have been attempting to devise various types of microscopes Based on the form of the illuminating radiation, there are mainly two types of microscopes that are used in the study of cells: the light microscope that exploits the characteristics of light and makes visible objects as small as 200 nm; and the electron microscope that makes use of a beam of electrons and has a resolving power of 0.2 nm, 1000 times

better than the resolution of a light microscope (ECB: 3) Within these two broad

types there are various subcategories Common types of light microscopes include: (1) the conventional light microscope, (2) the fluorescence microscope, which employs two barrier filters and fluorescent stains (rather than ordinary stains) and produces images of selected proteins or other molecules in bright glowing colour against a dark background, (3) the phase-contrast microscope, differential-interference-contrast microscope, and the dark-field microscope, which are used to visualize living cells, and (4) the confocal scanning microscope, which constructs images of complex three-dimensional objects Common types of electron microscopes include: (5) the

transmission electron microscope (TEM), (6) the scanning electron microscope (SEM), which gives three-dimensional images of surfaces and (7) the freeze-fracture and freeze-etch electron microscopes that visualize the interior of cell membranes and the exterior or interior of cells, respectively (Alberts et al 1994: 139-156)

The resulting micrographs vary accordingly in terms of both the Ideational meaning and Interpersonal meaning Ideationally, different types of micrographs show different things For instance, phase-contrast micrographs can show the structure of the living cell, and thus suit more a text that is describing the cell division and cell movement, and an ordinary light micrograph shows a structure of dead cells because before viewing the cell has been chemically fixed, or killed An electron micrograph,

on the other hand, is effective for showing fine details that light micrographs cannot achieve It is also obvious that there are overlaps in the functions of different micrographs (microscopes) For example, in addition to a light micrograph, an electron micrograph can also show the structure of the dead cell, but a possible drawback is that an electron micrograph may show too many gratuitous details

Interpersonally, all types of micrographs are machine inscriptions (Latour 1990: 35-36; Myers 1990: 238) and thus have the authority of presenting the true

“looks” of the cell, given the technology available at the time Indeed, in professional science, inscriptions are made to help to convince, win over, skeptical audience: “It [the trend toward inscriptions] is as necessary as the race for digging trenches on the front in 1914 He who visualizes badly loses the encounter; his fact does not hold” (Latour 1990: 41) At the same time, some types of micrographs such as the fluorescence micrograph have stronger interpersonal impact (“look better”) than other types such as the bright-field unstained light micrograph, since the former are in

superb colour against a dark background, while the latter show vaguely in black and white the outline of some cell components

Given the option of the word, the schematic drawing and the various types of micrographs, the reason why the textbook authors decide upon a particular type of presentation at a particular point in the text lies in the Ideational development of the co-text, the level of detail required (e.g a labeled schematic drawing shows more detail than a micrograph, which in turn shows more detail and specificity than the word), the Interpersonal stance the authors intend to take, and of course the availability

of the micrographs

5.3.2.2 Analysis of Figure 17-11 of Text 1

In Figure 17-11 (ECB: 557), we encounter a fluorescence micrograph, a micrograph

taken with the aid of a fluorescence microscope The co-text for Figure 17-11 is the first paragraph in the section “Chromosomes Line up at the Spindle Equator at Metaphase”, especially the following two clauses:

thereby forming the metaphase plate

This defines the beginning of metaphase (Figure 17-11)

The beginning of the paragraph of the main text describes a series of material processes and then gives a name to the stage of the development (intensive identifying process), while the figure shows a snapshot of a moment of the material processes, or the result of the preceding changes In freezing the moment, the dynamic nature of the change is lost but what is captured in the moment can be viewed closely and at leisure

Typographically, the figure is in the main text part of the page, the top left, and its caption is on the right as the marginalia I suggest that the reading path is as

follows: Step A the figure, Step B the title for the figure, and Step C the caption for the figure Figure 17-11, with the reading path marked with blue capitalized Roman letters

in italics, is reproduced in Figure 5.3 What follows is a selective analysis of the figure

B

Figure 17-11 Multiple mitotic

spindles at metaphase in a fruit fly

(Drosophila) embryo The

microtubules are stained red, and the chromosomes are stained green At this stage of Drosophila

development, there are multiple nuclei in one large cytoplasmic compartment, and all of the nuclei divide synchronously Although metaphase spindles are usually pictured in two dimensions, as they are here, when viewed in three dimensions the chromosomes are seen to be gathered at a plate-like region at the equator of the spindle– the so-called metaphase plate (Courtesy of William Sullivan.)

C A

Figure 5.3 Reading path for Figure 17-11

Step A The Figure

Interpersonally, this figure is very appealing It is arguable that the selection of a fluorescence micrograph in itself is an Interpersonal maneuver; the text, as does science in general, attempts to reach out to the student reader and the general public The factors that contribute to the interpersonal appeal of the figure include the following: (1) it deploys bright Colours: red, green, yellow and black (2) The Contrast in the colours is great: first, between the background black and the other colors and second, the contrast between red and green Of course, the outside of the