January 31, 1913] 



SCIENCE 



183 



is nothing of interest to the student of her- 

 petology in the first two chapters, on the 

 classification, evohition, history, distribution, 

 general habits and identification of species of 

 snakes, and the chapter on snake charmers, 

 Kafir superstitions, etc., and the one on hu- 

 man physiology may also be ignored. 



On the other hand, the herpetologist will 

 find much of interest in the accounts of the 

 habits of different species. The writer is evi- 

 dently a careful field observer, and his descrip- 

 tions of the feeding and breeding habits of 

 certain forms are a distinct contribution. 

 For example, the description of the feeding 

 habits of the puff adder (p. 225) could hardly 

 be improved. A very notable feature also is 

 the numerous photographs of snakes, both in 

 their natural haunts and in captivity. The 

 series showing a specimen of Dasypeltis scabra 

 eating an egg and ejecting the shell, and the 

 photographs of the mole snake, ringhals cobra, 

 and puff adder with newly born young are 

 notable, and there are many others of equal in- 

 terest. There is also a considerable amount of 

 information on the habitat preferences of 

 various forms that will be useful. 



The author is to be commended for the care 

 exercised in guarding against the errors that 

 are so liable to occur in a popular account. 

 The word skin is rather loosely used for the 

 stratum comeum in the account of sloughing 

 (p. 16) ; snakes do frequently eat dead ani- 

 mals in nature (p. 40) ; it is doubtful if many 

 naturalists still hold the opinion that the 

 fangs of opisthogljrphs are primarily for hold- 

 ing the prey (p. 139) ; and the toad is not a 

 reptile (p. 227). It is rather surprising that 

 the writer advocates sucking the woimd made 

 by the bite of a venomous snake, since this is 

 dangerous unless one is sure that there are no 

 abrasions about the mouth, and ISToguchi as- 

 serts that the procedure is quite useless. It 

 may be added that the author's style is rather 

 tautological, there is some irrelevant matter, 

 and a closer grouping of the subject matter 

 would be advantageous. 



The reviewer would suggest that an easy 

 key to the South African species would much 

 increase the value of the book. It is doubtful 



if many persons would take the trouble to dis- 

 sect out the jaws to identify the species; at 

 any rate it would not be easy to use the au- 

 thor's key, scattered as it is over several chap- 

 ters. 



Alexander G. Kuthven 

 Museum of Natxikal History, 

 University op Michigan 



General Physics. By W. Watson, F.E.S. 



Longmans, Green & Co. 564 pages, with 



311 figures and diagrams. 



It is a very interesting fact that Professor 

 Watson, who has given to us the comprehen- 

 sive " Text-book of Physics " with its nine 

 hundred and fifty pages, should find it neces- 

 sary to arrange another text to meet the needs 

 of " engineering, medical and other students." 

 Not only has he condensed and rearranged his 

 larger work, he has placed the emphasis on 

 different topics and has omitted many. 

 Among these may be noted the discussion of 

 the energetics of a voltaic cell and that 

 of Maxwell's electromagnetic theory. Fifty 

 pages in the older text are given to electrolysis 

 and electric cells where only sixteen are re- 

 quired in the new text. The three hundred 

 pages given to electricity and magnetism in 

 the older text have here been cut in half, not- 

 withstanding the fact that much new matter 

 is added on account of the discussion of radio- 

 activity and wireless telegraphy. 



It is rather probable that the newer text 

 will suit the needs of a larger number of in- 

 structors in general physics in American col- 

 leges than did the older text. For it can be 

 said that the table of contents includes all the 

 main essential principles of physics with a 

 reasonable number of applications to the af- 

 fairs of every-day life. The presentation is 

 direct, matter of fact, concise, clear. There 

 is no time or space for the spectacular or 

 ornate. The author, being an Englishman, 

 does not give an explanation, right or wrong, 

 of the curving of a base ball, nor of a tennis 

 ball — though had he done so he might have 

 claimed that he was but following the example 

 set by the illustrious Newton. Nor is the 

 mono-rail car discussed. But in America 



