958 LIFE : OUTLINES OF GENERAL BIOLOGY 



for coral, worm, or vertebrate. That Plato's archet3rpes were not 

 merely metaphysical or poetic ideas — ^but also owed not a little to 

 his strong geometric interests, is a view surely supported by the 

 rise, first of comparative anatomy and next of pure morphology, in 

 modem times; for surely he would have rejoiced with Goethe over 

 his understanding of the rose as essentially leafy, and his view of 

 the skuU as vertebrally segmented; for though that archetypal 

 concept has been proved faulty, it has none the less stimulated the 

 progress of morphology. In short, then, it needs but a little reflection 

 to see how thoroughly the progress of the sciences is in terms of that 

 of their graphic conceptions ; thus in passing from the Ptolemaic to 

 the Copemican system of astronomy, or with Pasteur considering 

 the build and behaviour of dimorphic crystals of tartaric acid, or 

 in comparing the forms of life, and their physiological changes as 

 well. We see, too, that graphics are by no means necessarily static; 

 but, indeed, serve kinetic uses above all. Hence that graphic imaging 

 which so largely occupied Kelvin's deep-searching mind, since he 

 was wont to say he could not really understand any physical concept 

 or process until he had conceived it in working model. 



In biologic studies, morphological and physiological alike, such 

 endeavours are invaluable: thus our studies of the plant are but 

 detailed, even dissociated, until we again bring them back into it 

 as a whole and in life; and thus see it as a working thought-model, 

 simultaneously exhibiting all we can learn from the special inquiries 

 of the sub-sciences. The great advances of the past generation from 

 simply descriptive embryography to much of rationally conceived 

 and kinetic ontogeny, in terms of growth and functioning in detail, 

 are obviously of this character. The long discussions of evolution, 

 even since Darwin, show that it has been not a little difficult to do 

 the like on the larger scale of phylogeny, i.e. for species, genera, 

 orders, etc. : but a very valuable and far-reaching advance was made 

 by Prof. D'Arcy Thompson in his Growth and Form (1917). For here 

 he presents growth as rationalising form ; a doctrine often generally 

 stated, but now traced more clearly and comprehensively than ever 

 before; and from cell to cell-bodies, from Protozoa to Mammalia. 

 The forms even of hard parts, from the shells of Foraminifera to 

 those of Molluscs, or again horns, teeth, and skeletons, are thus 

 shown as modelled by the plastic energies of growth; and this with 

 graphic clearness, and even frequent mathematical elucidation as 

 well. All this well prepares and leads the reader to his final chapter, 

 with its "Theory of transformations, or the comparison of related 

 forms", with his most vivid graphics of all. In popular teaching to 

 beginners in botany, we have used for illustration of the varieties 

 and changes of leaf -forms a model leaf, cut from a thin film of elastic 

 rubber: and still better, for complexer form-changes, the child's 

 amusing plaything of an india-rubber face, which is so readily 



