566 



SCIENCE 



[N. S. Vol. XL VI. No. 1197 



count is condensed to a bare outline of the 

 facts and points of view whicli the author con- 

 siders important. At the end there is an ap- 

 pendix on the general chemical composition of 

 organisms, followed by a large and varied liter- 

 ature list and an index of topics with the 

 names of the authors of the chief papers. 

 Much of the book thus forms a summary of 

 recent research, and will be valuable to those 

 desiring a record of progress in this field and a 

 guide to the literature of its various depart- 

 ments. 



The most original chapters are those relat- 

 ing to the determination of hydrogen-ion con- 

 centrations and the electromotor and osmotic 

 properties of partitions, and here there is 

 much that is ingenious, independent and sug- 

 gestive. The author's improved methods for 

 determining the H-ion concentration of blood 

 are described in detail, with figures of appa- 

 ratus and a useful chart for converting poten- 

 tials into H-ion exponents. The use of indi- 

 cators and buffer mixtures is also explained, 

 and many valuable data are given in con- 

 venient form. The account of semi-permeable 

 and porous partitions is especially timely and 

 interesting; the phenomena of membrane-po- 

 tentials, negative osmose and cell-permeability 

 are described, and their relations to the physio- 

 logical processes of secretion, absorption and 

 stimulation are discussed in a clear and defi- 

 nite manner. The author supports the view 

 that the bioelectric variations of jwtential are 

 primarily the expression of variations in the 

 osmotic and hence the electromotor properties 

 of the protoplasmic surface-layers or plasma- 

 membranes. Agents like salts, anaesthetics and 

 cytolytic substances are regarded as producing 

 their characteristic effects by modifying the 

 condition of the plasma-membranes. 



As a whole the book exhibits the defects as 

 well as the merits of its extreme brevity and 

 condensation. The author evidently wishes to 

 be as concise as possible, and largely for this 

 reason his discussion and statements of fact 

 frequently appear dogmatic and lacking in 

 much-needed qualifications. Certain explana- 

 tions are incomplete or otherwise open to criti- 

 cism. Thus to regard negative osmose as es- 



sentially a ease of electrical endosmose seems 

 inaccurate; in true electrical osmose both the 

 solution and the porous partition are inter- 

 posed as parts of an electrical circuit, and the 

 energy for the transport is derived from a bat- 

 tery or other external source; while in nega- 

 tive osmosis the water passes spontaneously 

 through the porous partition from the more 

 concentrated to the more dilute solution. Cer- 

 tain diffusion processes offer a closer analogy; 

 recent investigation has shown that when the 

 partition consists of negatively charged ma- 

 terial Hke porcelain negative osmose occurs in 

 the case of those electrolytes whose anions dif- 

 fuse more rapidly than their cations; and it 

 seems preferable to regard the positively 

 charged layer of water adjoining the surfaces 

 of the pores as acting like a layer of cations 

 and as being carried after the rapidly diffusing 

 anions by electrostatic attraction. The phe- 

 nomenon seems indeed to afford further evi- 

 dence of the hydration of ions in solution. Ex- 

 ception may also be taken to the following 

 statements: suspensoids do not exert osmotic 

 pressure (p. 72) ; monovalent and bivalent ca- 

 tions are antagonistic to each other in the pre- 

 cipitation of colloids (p. 77) ; surface-active 

 substances are repelled by water molecules (p. 

 66) ; in anaesthesia adsorption is at the basis of 

 the whole matter (p. 140. N". B. : this seems 

 contradicted by the positive temperature-coeffi- 

 cients of narcosis with chloral and alcohol as 

 observed by Meyer) ; the sperm need only 

 scratch the egg-surface to make it segment (p. 

 158) ; local reduction of surface-tension pro- 

 duces protrusion of the affected surface (p. 

 148). This last statement especially needs 

 qualifying; it can be true only when the sur- 

 face-tension equilibrates some other force 

 (such as gravity), which of itseK tends to 

 cause outflow or protrusion of fluid. The force 

 of surface-tension acts tangentially, hence the 

 surface-layer of fluid must always tend to be 

 drawn toward the regions where the tension is 

 highest; this removal of fluid from the areas of 

 lower surface-tension must (unless otherwise 

 compensated) cause there depression instead 

 of protrusion, as seen for instance in the case 

 of a layer of water to which ether or alcohol 



