Febeuaky 24, 1899.] 



SCIENCE. 



291 



not only bj^ the action of Routgen rays, but also 

 by extreme heat and by the chemical changes 

 that occur in flames. These cases are consid- 

 ered in the second part of the book. Here also 

 the effects are readily explained upon the 

 theory that the conduction is electrolytic. In 

 fact, it is the development of this theory in its 

 application to the various types of gaseous con- 

 duction that constitutes the most characteristic 

 feature of the book. An accidental error in 

 one of the formulas on page 37, whose conse- 

 quences appear also in some of the equations 

 on the two succeeding pages, may cause annoy- 

 ance to one reading hurriedly. A serious mis- 

 print occurs on page 42, where 10—" appears 

 several times as 10". 



An interesting account is given, in the second 

 division of the book, of the curious effect of 

 light in causing the discharge of negative elec- 

 tricity. This effect is produced chiefly by the 

 shorter light waves, and preeminently by the 

 invisible ultra-violet rays of the spectrum. It 

 depends not only upon the gas surrounding the 

 charged body, but also upon the nature of the 

 charged surface. The electro-positive metals, 

 such as zinc, sodium and rubidium, show the 

 effect best. The fact that phosphorescent sub- 

 stances are especially sensitive to this effect, 

 though as yet unexplained, is of undoubted 

 significance. 



The third section of the book, devoted to 

 cathode rays, contains an excellent account of 

 the recent experiments on this subject. Such 

 an account is of especial value because of the 

 extraordinary rapidity with which our knowl- 

 edge of these rays has advanced. It is interest- 

 ing to note that the study of cathode rays, as 

 well as the study of the other phenomena of 

 vacuum tubes, has received a fresh impetus 

 since the discovery of the X rays ; if this study 

 leads to important discoveries, as it now seems 

 almost certain to do, I think that these must 

 be regarded as indirect results of the discovery 

 ' of Rontgen. 



It is quite out of the question to call atten- 

 tion in this brief review to the many interest- 

 ing and important subjects that are discussed 

 throughout the book. The discussion is often 

 brief and lacking in the detail that would be 

 useful to one making a specialty of the subject. 



But the book is written by one whose own in- 

 vestigations have contributed largely to the 

 development of each of the topics considered, 

 and who is now engaged in further research 

 along the same lines. This fact gives to the 

 treatment a charm impossible of attainment 

 otherwise, and adds to the book a suggestive- 

 ness and inspiration which must appeal to all 

 who read it. Eenest Meeritt. 



Text-hook of Physiology. Edited by E. A. 



SCHAFER, LL.D., F.R.S. Vol. I. New 



York, The Macmillan Co. 



This new text-book of physiology follows out 

 the idea of combining under one editorship the 

 writings of different men who treat of the spe- 

 cial subjects in physiology with which they 

 have had personal and intimate experience. 

 In the face of the great and ever widening 

 scope of the science of physiology, no work of 

 general authority can be written in any other 

 manner to-day. 



In illustration of this we find in this volume, 

 which covers merely the chemical side of physi- 

 ology, reference to fully six thousand original 

 articles. The book is highly creditable to 

 the eleven English physiologists who have con- 

 tributed to it, and it strengthens the general 

 opinion that in physiology the English are sec- 

 ond only to the Germans. The Germans, how- 

 ever, have no such comprehensive and thorough 

 reference text-book as this. The work is hardly 

 one for medical students, but is intended for 

 the teacher, for the advanced investigator, or 

 for reference in the medical library. 



The article on the chemistry of the digestive 

 processes is ably written by B. Moore. He at- 

 tacks the theory of the cleavage of proteid into 

 two molecules, the ' hemipeptone ' and ' anti- 

 peptone,' for example, and claims that the ex- 

 istence of the 'hemi-' bodies has never been 

 proved. He suggests that trypsin may act on 

 a single molecule of albumose which may yield 

 a greater or lesser quantity of amido acids ac- 

 cording to the albumose used, and that the 

 residue of the molecule which cannot be further 

 attacked by trypsin is antipeptone. In the dis- 

 cussion of the composition of the fa3ces, Moore, 

 in common with almost every text-book of 

 physiology, makes the mistake of giving too 



