Apeil 2, 1909] 



SCIENCE 



547 



dyne is wrongly defined, velocity is wrongly 

 expressed. In a number of cases equalities and 

 proportionalities are used indiscriminately. 

 In fact, the book is logically weak, as would 

 be expected from the author's statement that 

 " inquiry into the rules of dynamics would 

 carry us too far afield." Much dynamics and 

 nauch mathematics are wholly unnecessary 

 for the purposes of this work, yet its merits 

 would be greatly increased by the more exact 

 use of the little necessary. The book is pro- 

 vided with a good table of contents and a 

 good index. It is well hound and excellently 

 printed. The misprints noted by the reviewer 

 are exceedingly few. 



S. J. Barnett 



Arbeiten aus dem, Gehiei der Experimentellen 

 Physiologie. Herausgegeben von Dr. Hans 

 Feiedenthal in Nicolassee bei Berlin. Mit 

 4 Tafeln und 14 Figuren im Text. Jena, 

 Gustav Fischer. Pp. 493. 1908. Price, 

 8 Marks. 



This' collection of papers by Dr. Frieden- 

 thal and his collaborators has been prepared 

 in order to bring together a number of contri- 

 butions scattered throughout various scientific 

 journals, some of which are not easily ac- 

 cessible, and to make them readily available 

 to physiological readers. They have been ar- 

 ranged by the editor, with relation to their 

 content, into the following groups : biological 

 relationships among animals and plants; 

 papers on physiological operative technic, in- 

 eluding studies on absorption, the innervation 

 of the heart, and the sympathetic system; 

 studies on physical and physico-chemical 

 topics ; papers on the H-ion concentration and 

 the reaction of living substance; and addi- 

 tional contributions of diverse character. 



It is impossible here to refer individually to 

 the 55 papers reprinted. Many of them are 

 already quite familiar to biological and phys- 

 iological workers. This applies, for example, 

 to studies such as those dealing with the fate 

 of foreign sera introduced into the circulation 

 of animals, and with the nature of the forces 

 coming into play during the act of absorption. 

 Friedenthal defends the view that solubility 

 in water is per se insufficient to determine the 



possibility of absorption of substances by cells. 

 We are asked to distinguish between solubility 

 in protoplasm and solubility in water; herein 

 the now well-recognized importance of the cell 

 lipoids for the processes under discussion is 

 duly emphasized. The author has further- 

 more especially insisted upon the absence of 

 special " vital " forces in absorption. 



Friedenthal's earlier observations on the bio- 

 logical relationships of animals and the posi- 

 tion of man in the zoological scheme were 

 jierhaps not as widely known at the period of 

 their publication as they deserved to be; the 

 so-called " immunity " reactions which were 

 shown in common for man and the anthropoid 

 apes have since been more extensively ob- 

 served. 



Some of the observations on the occurrence 

 and nature of enzymes have more recently 

 lost the significance attributed to them when 

 they were first published. Thus Friedenthal's 

 announcement of the existence of an amylo- 

 lytic enzyme in the gastric juice of dogs is 

 probably referable to the regurgitation of in- 

 testinal contents (including pancreatic secre- 

 tion) into the stomach — a phenomenon shown 

 by Boldireff to occur with frequency in these 

 animals. 



The most significant of all the reprinted 

 papers are, perhaps, those dealing with the 

 reactions of the blood and protoplasm. Fried- 

 enthal was among those first to point out the 

 non-existence of an alkaline reaction in the 

 blood in reference to indicators sensitive to 

 carbonic acid; and he showed the importance 

 of the alkali bicarbonate of the serum as a 

 regulatory factor in preventing marked varia- 

 tions from neutrality. These investigations 

 were followed by the publication of a compara- 

 tively simple method for the estimation of the 

 reaction of physiological fluids by the use of 

 a series of indicators. The method, which 

 has already found application in the study of 

 physiological problems, is likely to be a help 

 in future research, especially in the study of 

 such questions as acidosis. 



Lafayette B. Mendel 



Sheffield Scientifio School 

 OP Yale University, 

 New Haven, C!onn. 



