404 THE STRUCTURE OF EVOLUTIONARY THEORY
formation even of a number of concentric rings of different colors from an
animal pigment by the even diffusion of one reagent from a center occurs
actually in Gmelin's test for bile-pigments. Bile is spread on a white plate
and a drop of nitric acid yellow with nitrous acid is dropped on it. As the
acid diffuses itself distinct rings of yellow, red, violet, blue, and green are
formed concentrically around it by the progressive oxidation of the bile-
pigment ... This example is merely given as an illustration of the possibility
that a series of discontinuous chemical effects may be produced in
concentric zones by a single central disturbance (1894, p. 292).
Rarely missing an opportunity for a dig at Darwinism, Bateson then adds that,
with the chemical analogy, we at least hope to find a cause, whereas the standard
adaptational speculation can make no such claim: "As to the function of the ocellar
markings nothing is known, and I am not aware that any suggestion has been made
which calls for serious notice" (1894, p. 294).
Writing more generally on the same theme, Bateson tries to attribute discrete
color classes directly to the chemical stability of pigments—and to dismiss the
alternative functional explanation of adaptational guesswork about the utility of
discontinuous difference. (This passage occurs in Bateson's only short discussion
of substantive rather than meristic variation—the category intrinsically less
favorable to his preference for discontinuity. Thus, he strives for explanatory
generality across all classes of variation): "It would, I think, be simpler to regard
the constancy of the tints of the several species and the rarity of the intermediate
varieties as a direct manifestation of the chemical stability or instability of the
coloring matters, rather than as the consequences of environmental selection for
some special fitness as to whose nature we can make no guess. For we do know the
phenomenon of chemical discontinuity, whatever may be its ultimate causes, but of
these hypothetical fitnesses we know nothing, not even whether they exist or no"
(1894, p. 48).
In his summation, Bateson reiterates his conviction that meristic discontinuity
may represent a necessary phenotypic expression of an underlying mechanical
regularity, and not a set of adaptations gradually crafted by natural selection: "To
sum up: There is a possibility that meristic division may be a strictly mechanical
phenomenon, and that the perfection and symmetry of the process, whether in type
or in variety, may be an expression of the fact that the forms of the type or of the
variety represent positions in which the forces of division are in a condition of
mechanical stability" (1894, p. 71). In addition, Bateson could not resist a final and
explicit anti-Darwinian dig in stating that such symmetrical forms would "owe
their perfection to mechanical conditions and not to selection or to any other
gradual process" (1894, p. 70).
SUSPICION OF HISTORY (AS WELL AS ADAPTATION) AS A CAUSE OF
MORPHOLOGY. The pure formalist or structuralist not only rejects functional
accounts based on slow building for utility, but also tries to avoid any appeal to
deep history in explaining the origin of morphology. The pure structuralist prefers
ahistorical accounts (see Chapter 11, Section 1, for modem versions),