538 Mr. C. F. M. Swynnerton on 



attention drawn for years to the scantiness of tlie evidence. 

 How mnch more intelligible is it that we should liave 

 accumulated little evidence on a possibility to which our 

 attention has never till now been drawn ? 



(3) Acceptances were regarded as showing Tndiscriminaie- 

 ness. — As Mr. Jourdaiu very truly said, the Carrion-Crow 

 devours all kinds of eggs. It would be surprising if it did 

 noi, for a hungry animal ivill eat almost anything that comes 

 within the category of its natural prey. But this does not 

 necessarily imply indiscriminateness. The wild bird on 

 which I experimented most largely was an individual of 

 Dryoscopus guttatus. When hungry enough, as it frequently 

 ■was, it would readily accept the most nauseous insects I 

 could offer it, and its acceptances of such extremely low-grade 

 butterflies as the Danainse and Acr^einae, witnessed by myself, 

 perhaps nearly equal all other records put together — the 

 very records on which critics have relied to demolish the 

 theory of mimicry. Yet this self- same Shrike was a most 

 discriminating bird ! It only took two or three acceptances 

 when it was at its hungriest to carry it beyond the Acraa- 

 accepting stage, and, as it gradually filled up, it discarded 

 species after species until, nearing repletion-point, there 

 were only a few species left that it would accept at all. 

 The same may be quite true of the Carrion-Crow. 



Or, of course, it may not. Numerous insectivorous birds 

 are as discriminating as the Dryoscopus. A few, however, 

 fill up very considerably before they commence to dis- 

 criminate — at any rate, in relation to certain large classes 

 of prey. iSome, again, are specialized to feed nearly to 

 repletion on what are, to other birds, the most nau>eous 

 of insects. The case of the lemur suggests a likelihood of 

 similar variation in digestive capacity amongst egg-eaters. 



Mr. Stuart Baker mentioned that he had not experimented, 

 but he had kept egg-eating birds and mammals and noticed 

 no discrimination. My own non-experimental experience 

 (though in another connection) was entirely the same as his, 

 and I will use it to illustrate the difference between casual 

 offerings and carefully-conducted experiment. Long ago I 



