538 



SCIENCE. 



[N. S. Vol. XVll. No. 431. 



8. Sex-char.acters segregate at the second 

 (the 'reduction') maturation division. For 

 eggs which develop without fertilization 

 and without a second maturation division 

 contain both the male and the female char- 

 acters, the former recessive, the latter 

 dominant. But, in normally partheno- 

 genetie species, eggs which undergo a sec- 

 ond maturation division and then develop 

 without fertilization are always male. In 

 such species the female character regularly 

 passes from the egg into the second polar 

 cell; in dioecious animals either sex-char- 

 acter may remain in the egg. 



GiLMAN A. Drew, 

 Secretary (Eastern Branch) . 



University of Maine. 



SCIENTIFIC BOOKS. 

 Die BiogenJiypothese. Sine hritisch-experi- 



mentelle Studie uber die Vorgdnge in der 



lebendigen Suhstanz. By Max Verwoen. 



Jena, Gustav Fischer. 1903. 8vo. Pp. 



114. 



To coiLsolidate the ideas which are present- 

 ing themselves more or less obtrusively to the 

 minds'of all workers in the biological sciences, 

 and to give them concrete expression, is an 

 accomplishment of no little importance, and 

 it is this which Professor Verworn has at- 

 tempted in propounding his Biogen-theory. 

 Biogen is the special constituent of proto- 

 plasm whose decomposition and recomposition 

 are the basis of the phenomena which we 

 recognize as life, and the paper now under 

 review is an examination into the nature of 

 vital phenomena and an endeavor to deduce 

 from this examination what the general com- 

 position and structure of the biogen molecules 

 must be. 



In its essence Verworn's theory differs but 

 slightly from that advanced by Pfliiger many 

 years ago; it does differ, however, in its de- 

 tails. For it recognizes the similarity of the 

 chemical processes taking place in the cell to 

 those manifested during the action of an en- 

 zyme, accepting the prevalent view that an 

 enzyme acts as a catalyzing agent and that 

 the action of a catalyzer is the formation of 



a labile intermediate product which instantly 

 decomposes, restoring the catalyzer to its 

 original condition. Enzymes exist in the 

 living substance which are capable of bring- 

 ing about complicated syntheses and have the 

 power of producing by their activity addi- 

 tional quantities of themselves; such phe- 

 nomena demand the assumption that even 

 in the molecules of the enzyme metabolism 

 occurs and the biogen molecule may be re- 

 garded as something similar to such an en- 

 zyme. 



Assuming this idea as a foundation, what 

 may be predicated concerning the special com- 

 position of the biogen molecule? It is well 

 known that an increase in the amount of 

 oxygen increases, and a diminution of it 

 diminishes, the irritability of the living sub- 

 stance, and Professor Verworn believes that 

 it has been established by his own observa- 

 tions and those of his pupils on strychninized 

 frogs that this phenomenon depends upon an 

 increase in the lability of the biogen mole- 

 cules in the presence of oxygen, and a diminu- 

 tion of it in the absence of that substance. 

 If this be true, then it may be assumed that 

 there is in the biogen molecule a chemical 

 group which reacts readily with oxygen, and, 

 since the functional activity of muscle, for 

 instance, is associated, as Hermann demon- 

 strated long ago, with the formation of non- 

 nitrogenous products of decomposition, it may 

 be supposed that the reacting group is a car- 

 bohydrate group, or, perhaps, on account of 

 its affinity for oxygen, a carbon group of the 

 type of a carbohydrate with a terminal alde- 

 hyde group. 



But in addition there must also be a nitrog- 

 enous group in the molecule, since a continu- 

 ous nitrogenous catabolism is going on in the 

 tissues, and that this group is probably of the 

 benzol type is shown by the formation of 

 aromatic decomposition products, such as 

 tyrosin, indol, phenol, skatol, etc., as the re- 

 sult of the digestion or putfefaction of albu- 

 men compounds. For the building up of a 

 complicated organic compound a benzol group 

 presents many possibilities, and Verworn sup- 

 poses that such a group forms the center of a 

 biogen molecule and that the carbohydrate 



