December 30, 1909] 



NA TURE 



H7 



mention one only. From my personal experience I am 

 utterly unable to' discover any distinction at the time of 

 perception between a visual image in waking life and one 

 in a vivid dream. It may be that afterwards I recognise 

 that the latter were onlv baseless visions, but not, as a 

 rule, from any quality o'r deficiency in the visual percept 

 itself. I am aware that it has been suggested that even 

 in dream images the retina is in some obscure way con- 

 cerned, but this assumption seems to me quite gratuitous ; 

 it is not, so far as I know, supported by any evidence, 

 and ought to be cut off by the razor of Occam. 



Edward T. Dixon. 

 The Hard, Hythe, Southampton, December 5. 



The Coloration of Birds' Eggs. 

 Without wishing to trespass further than I can help 

 upon the space at disposal for discussing this topic, I may 

 just explain that in my reply to Mr. Leslie, June 11, 1908, 

 I distinctly gave it as my opinion that coloration had no 

 connection with Mendelian principles. I concluded that 

 coloration often depended on habitat, and was now useful 

 as a means of protection ; but the habitats (and nesting 

 sites) of birds change, hence the anomalies met with which 

 are cited as diiiculties. 



As to the colour-changes of the chameleon, Mr. Leslie 

 ought to remember that this is an act of the animal itself, 

 and a distinctly psychic act, in no way connected with 

 reproduction. The coloration of the bird's egg is 

 primarily the application of a pigment — depending in 

 intensity on health and age — by the bird upon a product 

 which has already ceased to form an integral part of the 

 animal before the pigment is applied; and the bird's egg 

 is not — like the mollusc's shell — an organic complement 

 of the animal producing it. One might as well try to 

 trace the evolution of a bird from the track of its foot 

 in the sand as from the coloration of its egg ! 



So the parallel is inadmissible for this simple reason 

 alone, apart from many others. Moreover, if number, 

 form, size, texture in the shell itself have some morpho- 

 logical significance in relation to the bird's oviduct and 

 secretory sacs, being also determined earlier in the phylo- 

 geny (as in the individual's ontogeny) of the group, colora- 

 tion has little, except upon the selection and store of 

 pigment ; and the saurian and early avian eggs, further- 

 more, were uncoloured. 



Thus coloration is a recent acquisition, which, as I have 

 already pointed out, is intimately related — just as eggs and 

 classification are, to some extent — to habitat, allied species 

 (even genera or groups) laying allied types of eggs, adopt- 

 ing the same mode of life and nesting site. Thus it is 

 a physiological adaptation, and as such cannot explain 

 morphological origins, though as cause and effect we may 

 compare coloration and protection from enemies, &c. In 

 a word, coloration exists for concealment, and markings 

 (e.g. the black blotch on the cuckoo's egg) for identification. 



A. R. HoRWOOD. 

 Leicester Corporation Museum, December 20. 



Mitchell's testimony as to the accuracy of their reri- 

 dering, can we congratulate the translators on their 

 style. "The menagerie owner Malforteiner " (p. 226) 

 is not, for instance, elegant English ; while a sentence 

 on p. 153 conveys the astounding statement that Mr. 

 Hagenbeck walked off with the fore-leg of a live 

 elephant. On p. 157, as in many other places, we 

 find '■ which " repeated in the first half of a very short 

 sentence; and on p. 168 we find it stated that "this 

 species is often captured, but in captivity they are 

 very liable to die." On p. 58 the word "lime," in 

 place of "bird-lime," completely spoils a sentence. 



Mr. Hagenbeck commences his narrative with an 

 account of his early life, in the course of whichhe tells 

 his readers how he was initiated into the business of 

 buying and exhibiting animals by his father, who 

 took it up as a kind of supplement to his own proper 

 trade late in life. When he once felt his feet, the 

 author of the present volume forthwith proceeded to 

 organise the trade of wild-beast catching on thoroughly 

 business lines; and as he is the only man that has 

 done so, the consequence is that he has practically 

 monopolised the whole trade. Although it at times 



THE CAPTURE AND TRAINING OF WILD 

 ANIMALS A 



THE name of Carl Hagenbeck has attained such 

 world-wide celebrity that a volume from the pen 

 of the great animal-dealer and animal-tamer must 

 surely receive a hearty welcome from the reading 

 public. The publishers have therefore been well advised 

 in bringing out an English edition of the original 

 German work, although they might have taken care 

 that it bore on the title-page some indication of its 

 being from the pen of Mr. Hagenbeck himself. 

 Whether the title is an exact translation of the German 

 one we are unable to say, but if it be so, a slight modi- 

 fication would have been advisable, as it certainly does 

 not read well in English. Neither, in spite of Dr. 



I " Beasts and Men, being Carl Hagenbeck's Experiences for Half a 

 Century among; Wild Animals." An abridged translation by H. S. R. 

 Elliot and A. G. Thacker,-with an introduction by P. Chalmers Mitchell. 

 Pp. xiii-|-29Q; illustrated. (London: Longmans, Green and Co., 1909.) 

 Price izs. 6d, net. 



NO. 2006, VOL. 82] 



undoubtedly yields large profits, and is always full of 

 interest to a man of enterprise and resource, the trade 

 is full of risk, and demands great stability of character 

 and perseverance in the face of losses on the part of 

 those bv whom it is conducted. We hear, for in- 

 stance, of a loss of 10,000/. owing to disease seizing 

 a collection of animals at the Crystal Palace for which 

 that sum had been offered ; while a sum of 5000L was 

 lost in two unsuccessful expeditions dispatched to 

 Central Asia for the purpose of capturing argali sheep. 

 The sheep were, indeed, captured right enough, but 

 all died on the way home. 



One of Mr. Hagenbeck's periods of great prosperity 

 took place in the middle 'sixties and up to 1876, when 

 an enormous number of live animals was brought out 

 of the Egyptian Sudan. The menageries of the world 

 were, however, overstocked, and about the year 1877 

 the author had almost to give away giraffes : this 

 state of affairs induced him to take up the exhibition 

 and training of animals in an establishment of his 

 own — a branch of his business which culminated in the 

 inauguration of the present animal-park at Stellingen. 

 One of his earliest experiments in this direction was 



