146 



SCIENCE. 



[N. S. Vol. XXIV. No. 605. 



says further that we m-ust admit " that noth- 

 ing contradicts the possibility that the arti- 

 jS.cial producion of living matter may one day 

 be accomplished. It i& the purpose of these 

 lectures to state to what extent we are able 

 to control the phenomena of development, 

 self-preservation and reproduction. * * * We 

 shall only go far enough to satisfy ourselves 

 that no variables are found in the chemical 

 dynamics of living matter which can not be 

 found also in the chemistry of inanimate 

 nature." 



In lecture H. the author deals with the gen- 

 eral chemistry of life phenomena. Ferments 

 and oxidation are the chief subjects of dis- 

 cussion. The idea of ' catalytic processes be- 

 tween tissues and liquids ' was introduced by 

 Berzelius, and Ostwald has shown that cat- 

 alyzers do not initiate, but only accelerate 

 reactions. The discovery by Crofton Hill 

 and by Kastle and Loevenhart of the reversible 

 action of enzymes is discussed; and also the 

 observations by Neilsen of the reversibility of 

 action by an inorganic catalyzer (platinum 

 black) and that the effects of certain poisons 

 are the same for both organic and inorganic 

 catalyzers. Respiration as a catalytic process 

 is considered. The possibility of two groups 

 of oxidizing catalyzers is suggested: one, of 

 the type of the peroxides, may be present in 

 the protoplasm; and the second, which can act 

 indefinitely as oxidases, may be found in the 

 nucleus. Loeb calls attention to the fact that 

 oxygen not only supplies potential and kinetic 

 energies, but is also important for cell division 

 and growth, and acts as ' protective ' agent. 

 Lack of oxygen causes structural changes. 

 Experiments which show the production of 

 CO, by enzymes are reported. Concerning 

 the theory of enzyme action Loeb gives a brief 

 statement of the attempt in the stereochemical 

 direction; but he is rather inclined to accept 

 the theory of intermediary reaction. Every- 

 thing seems to indicate that enzymes form un- 

 stable combinations with the bodies whose 

 reactions they accelerate. 



In lecture III. under the head of the general 

 physical constitution of living matter are dis- 

 cussed: the limits of divisibility of living 

 matter; Biitschli's views that living proto- 



plasm has the structure of a microscopic emul- 

 sion; the colloidal character of living matter; 

 the formation of semipermeable membranes. 

 Loeb gives here the Meyer-Overton theory of 

 anesthesia with which he does not fully agree. 

 " The rapidity of the absorption of narcotics 

 may be due to their solubility in oil, and yet 

 the effect they produce may be due to some- 

 thing entirely different." With regard to the 

 role of osmotic pressure and the exchange of 

 liquids between the cell and the surrounding 

 liquid, to the discussion of which a few pages 

 are devoted, it may be mentioned that Loeb 

 says he now believes ' that contractile phe- 

 nomena inside the cell furnish at least part of 

 the energy of secretion and absorption in those 

 cases where the osmotic forces alone can not 

 explain these phenomena.' In the same lec- 

 ture an account is given of Loeb's extensive 

 experiments on the antagonistic effects of salts. 



In lecture IV. some physical phenomena of 

 life are discussed: the theories of muscular 

 contraction, of protoplasmic motion, of cell 

 division; the origin of radiant energy (phos- 

 phorescence) and the electrical phenomena in 

 living organisms. 



Lecture V. is on the role of electrolytes in 

 the formation and preservation of living mat- 

 ter, Loeb gives here among other things a 

 condensed but clear account of the very ex- 

 tensive and important studies by himself and 

 his pupils on ion-proteid compounds and their 

 relations to contractile tissues. The articles 

 dealing with these subjects are very numerous 

 and scattered in many publications, not all of 

 which are easily accessible. The knowledge 

 of these articles is quite indispensable for a 

 student in general physiology. It is gratify- 

 ing, therefore, to have an authoritative ac- 

 count of the entire subject presented in only 

 thirty pages. 



Lecture VI. deals with the effects of heat 

 and radiant energy upon living matter. 



Lectures VII. and VIII. are devoted to a 

 discussion of the different tropisms, to the 

 knowledge of which in the animal world the 

 author has, as is well known, contributed 

 pioneer work. 



In lecture IX., on fertilization, the reader 

 will find among other things a lucid account 



