tag="{http://www.w3.org/1999/xhtml}a">309

105. Sheep. Drawn from life 310 106. Cattle. Drawn from life 311 107. Wild Boar contrasted with a modern Domesticated Pig 312 108. Seasonal changes of colour in Ptarmigan (Lagopus mutus) 317 109.Œdicneus crepitans, showing the instinctive attitude of concealment 320 110. Imitative forms and colours in insects 322 111. The larva of Puss Moth (Cerura vinula) 325 112. The larva of Puss Moth in disturbed attitude 326 113. Three cases of mimicry 328 114. Two further cases of mimicry; flies resembling a wasp in the one and a bee in the other 329 115. A case of mimicry where a non-venomous species of snake resembles a venomous one 330 116. A case of mimicry where a homopterous resembles a leaf-cutting ant 332 117. Feather-footed pigeon 359 118. Raia radiata 368 119. Electric organ of the Skate 369 120. Electric cells of Raia radiata 370 121. The Garden Bower-bird (Amblyornis inornata) 382 122. Courtship of Spiders 388 123. Courtship of Spiders (continued) 389 124. The Bell-bird (Chasmorhynchus niveus) 396 125. C. tricarunculatus 397

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SECTION I

EVOLUTION

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CHAPTER I.

Introductory.

Among the many and unprecedented changes that have been wrought by Mr. Darwin’s work on the Origin of Species, there is one which, although second in importance to no other, has not received the attention which it deserves. I allude to the profound modification which that work has produced on the ideas of naturalists with regard to method.

Having had occasion of late years somewhat closely to follow the history of biological science, I have everywhere observed that progress is not so much marked by the march of discovery per se, as by the altered views of method which the march has involved. If we except what Aristotle called “the first start” in himself, I think one may fairly say that from the rejuvenescence of biology in the sixteenth century to the stage of growth which it has now reached in the nineteenth, there is a direct proportion to be found between the value of work done and the degree in which the worker has thereby advanced the true conception of scientific working. Of course, up to a certain point, it is notorious that the revolt against the purely “subjective methods” in the sixteenth century revived the spirit of inductive research as this had been left by the Greeks; but even with regard to this revolt there are two things which I should like to observe.

In the first place, it seems to me, an altogether disproportionate value has been assigned to Bacon’s share in the movement. At most, I think, he deserves to be regarded but as a literary exponent of the Zeitgeist of his century. Himself a philosopher, as distinguished from a man of science, whatever influence his preaching may have had upon the general public, it seems little short of absurd to suppose that it could have produced any considerable effect upon men who were engaged in the practical work of research. And those who read the Novum Organon with a first-hand knowledge of what is required for such research can scarcely fail to agree with his great contemporary Harvey, that he wrote upon science like a Lord Chancellor.

The second thing I should like to observe is, that as the revolt against the purely subjective methods grew in extent and influence it passed to the opposite