74 Bibliographical Notice. 



BIBLIOGEAPHICAL NOTICE. 



The Penycuik Experiments. By J. C. Ewaet, M.D., F.R.S., Regius 

 Professor of Natural History, University of Edinburgh. (A. & C. 

 Black.) 8vo. London, 1899, Pp. xciii, 177, with 46 illustrations 

 distributed through text, process, mostly from photographs. 



Unfortt7NATELT the title of this volume appears to be defective or 

 misleading, and probably ought to have read ' Penycuik Equine 

 Experiments.' The author may be surprised one day, should he 

 find it in some library catalogues classed under currency-question 

 subjects — for such things, and even stranger ones, not unfrequently 

 happen. The binding of the book may save this contingency, 

 for its zebrine style is strikingly characteristic. Once for all, we 

 may say the illustrations are very effective (especially those of the 

 foals and of the heads), showing the body, legs, and face-markings. 

 At first we thought the repetition of a few of the figures was a 

 mistake ; but careful study of the text has led us to a different 

 conclusion. 



The somewhat long introduction (93 pages) is devoted to a 

 consideration of zebra hybrids generally, to the principles of breeding 

 of various domestic animals, to telegony ( = infection), to saturation 

 ( = absorption of some of the elements or nature of parentage), and 

 to sterility in equine hybrids. Then follows Part I., containing : — 



A. The birth of a hybrid between a Burchell's zebra and a mare ; 



B, The zebra-horse hybrids. 



Part II. enters into a more detailed or specific account of tele- 

 gony, with observations on the striping of zebras and horses and on 

 reversion in the Equidae. An appendix to the latter deals chiefly 

 with letters and observations of others on telegonal experimental 

 breeding, and it ends with remarks on the desirability of trial of 

 some fifteen different sorts of crosses between the horse tribe, cattle, 

 sheep, and swine. 



A considerable portion of the contents of this book has at various 

 intervals appeared as contributions to ' The Veterinarian,' and one 

 paper in ' The Zoologist,' besides lectures delivered at the Royal 

 Institution. To a certain section of the public then it is not entirely 

 new matter; but as collected in one handy illustrated volume it 

 will be much more accessible to naturalists and the general public, 

 many of the latter now taking a deep interest in this and cognate 

 subjects. 



So far as we can judge, we believe we are in approximate agree- 

 ment with the quintessence of Prof. Ewart's volume, namely, his 

 views on Reversion ; yet at the same time we may own to at first 

 having been bewildered by the reiteration of data and the same 

 differently expressed. This leads us to think that, instead of re- 

 piinting the separate papers previously published in journals, and 

 endeavouring to connect them together by a general introduction, 

 the author himself saying " which must also serve as a preface and, 

 to a certain extent, as a supplement," it would have enhanced the 

 work if it had been entirely recast into a continuous whole. But 



