412 



NA TURE 



[March 4, 18S6 



exceptions that, instead of weekly sums of tlie rates being j 

 given, the sums are given for every ten days, and the j 

 Centigrade thermometer is used. The chronometers are i 

 also kept in a constant temperature for each ten days of | 

 the period of trial, commencing with 15^ C, then with the i 

 temperature raised 5^ for each decade until the maximum, 

 30°, is reached. The trials are continued in the same 

 manner with decreasing temperatures until 5 ' is reached, 

 and lastly with temperatures increasing to 30" as before. 



From what has been said it will be seen that at the 

 Naval Observatory in Hamburg a wide range of subjects 

 is taken under its supervision, and it may be added that 

 the volume now under review is a full and able exponent 

 of its work and aims. 



VARIATION IN DOMESTICATED ANIMALS 

 Fancy Pigeons. By J. G. Lyell. 

 Poultry for Prizes and Profit. By J. Long. 

 Book of the Goat. By H. Holmes Pegler. 

 British Cage-Birds. By R. L. Wallace. (London : L. 



Upcott Gill, 1885.) 

 ■^ 5 rE have grouped the above-named works together 

 inasmuch as they all treat of the varieties existing 

 in domesticated animals, and are moreover serials in 

 course of publication by the same publisher. 



Previous to the issue of Darwin's great work on 

 " Variation in Plants and Animals," the subject was 

 treated with undisguised contempt by biologists gene- 

 rally, and thought to be worthy of consideration only by 

 florists and fanciers, not even its importance in reference 

 to the food supply of man being properly estimated. 

 The origin of this opinion was no doubt correctly given 

 by the late Dr. Gray, when, in reply to the question put 

 to him by the writer of this notice, "Why naturalists 

 ignored the existence of varieties, a variation, however 

 abnormal or monstrous it might appear, being as real as 

 the most norma! species," he answered, " The reason, my 

 dear sir, is that they know nothing at all about them." 



Nor is this ignorance extinct at the present day. In 

 the Museum of the College of Surgeons may be seen the 

 skull of a crested fowl, with the peculiar bony growth 

 supporting the crest, and the accompanying hour-glass- 

 shaped cavity of the cranium, which are characteristic of 

 the entire race, described as the result of disease in the 

 catalogue compiled by Sir Richard Owen. Nor need we 

 go further than our own unrivalled zoological vivarium to 

 see specimens which every breeder of domestic animals 

 believes to be mere varieties, such as woolly cheetahs 

 and black-shouldered peacocks, exhibited as " good 

 species." 



How many naturalists even now care to ascertain what 

 are the limits of variation in any given species, or to what 

 extent the characteristics of allied animals or groups of 

 animals may be reproduced by what Darwin termed 

 " analogous variation." 



By careful selection, aided by great practical expe- 

 rience, the skilled breeder can produce almost any pattern 

 of plumage or any disposition of colour he pleases, limited 

 only by the range of colours and markings natural to other 

 animals of the family to which the species belongs on 

 which he is experimenting Thus all the markings of the 

 wild Felida: can be reproduced in the domestic cat ; those 



of the Columbidffi in the pigeon ; but the feline mark- 

 ings cannot be produced in the dog, nor the distribution 

 of colour seen in the .Australian pigeons be implanted in 

 the domestic fowl. 



It unfortunately happens that the peculiar bent of mind 

 which makes a man a "good fancier " does not necessarily 

 tend to constitute a good naturalist, and it is rare for the two 

 pursuits to be combined in the same person ; the zoologist 

 despising the fancier and his monstrosities, which are the 

 result of aiiificial selection, and the fancier, on the other 

 hand, if he has even a slight acquaintance with zoology, 

 laughing at the naturalist who manufactures what he 

 calls "good species" out of a slight variation of plumage, 

 which he, the fancier, would breed to order without the 

 slightest difficulty. For examples of this proceeding, we 

 need only turn to recently manufactured species of the 

 genus Phasianus. 



To those ornithologists who would wish to note the 

 almost infinite variety of pattern, colouration, and marking 

 to which the descendants of Coluniba livia can be 

 bred, we would recommend the " Fancy Pigeons " of Mr. 

 Lyell ; it contains a more detailed and fuller account of 

 the numerous breeds than any book in the language, 

 although some of the theories of the writer will not 

 meet with the support of ornithologists. The work, 

 moreover, has a sufficient number of engravings, 

 both coloured and plain, to render the descriptions 

 easy to follow ; and these are not, as is too often the 

 case in works written by a fancier for fanciers, grossly 

 exaggerated. 



" Poultry for Prizes and Profit" treats, as far as it has 

 proceeded, of the characteristics of the various breeds of 

 fowls, of which, as of pigeons, new varieties are being 

 constantly produced. Of the manner in which fanciers 

 confound species and varieties a strong example is given, 

 the author describing the very distinct and strongly cha- 

 racterised species. Callus furcatus, as a variety of the 

 domestic fowl. 



The " Book of the Goat " contains a very good descrip- 

 tion of the various breeds of goats found in different 

 parts of the world, and most valuable and practical direc- 

 tions for the management of the animal in a domestic 

 state as a useful milk-producer. 



" British Cage-Birds," the last of the serials on our list, 

 deals more with wild species than with varieties. It gives 

 the mode of capture, treatment in captivity, &c., of 

 British birds that are kept in confinement for the sake of 

 their song or beauty of plumage. This work is also 

 largely illustrated, but the engravings in many instances 

 are capable of improvement. 



W. B. Tegetmeier 



OUR BOOK SHELF 

 Differential and Integral Calculus, with Applications. 



By A. G. Greenhill,'M.A. Pp. xi. and 272. (London: 



Macmillan and Co., 1886.) 

 Within the limits of 267 pages it is not easy to make 

 improvement in so vast a subject as that of this treatise. 

 The chief novelty is the concurrent treatment of differen- 

 tial and integral calculus. A great step in perspicuity 

 has been made by the use of the complete notation 

 of hyperbolic trigonometry (sinh, cosh, &c., and sinh"', 

 cosh"', &c.), which shows the perfect analogy of the 



