GENERAL CHEMISTRY OF LIFE PHENOMENA 21 



from about one hundred to twenty or ten per minute : then it continues 

 to beat at this rate for ten hours or more. In this case one might 

 believe that during the period of steady diminution of the tension of 

 oxygen in the heart (during the first hour), the heartbeat sinks steadily, 

 while it keeps up at a low but steady rate as long as the energy for the 

 beat is supplied solely by hydrolytic processes ; but there is certainly no 

 change in the physical structure of the cells noticeable in Fundulus, 

 and consequently there is no sudden standstill of the heart. 



Budgett has observed that in many Infusorians visible changes of 

 structure occur in the case of lack of oxygen ; * as a rule the membrane 

 of the Infusorian bursts or breaks at one point, whereby the liquid 

 contents flow out. Hardesty and I found that Paramcecium becomes 

 more strongly vacuolized when deprived of oxygen, and at last bursts. 

 Amcebas likewise become vacuolized and burst under these conditions. 

 Budgett found that a number of poisons, such as potassium cyanide, 

 morphine, quinine, antipyrine, nicotine, and atropine, produce struc- 

 tural changes of the same character as those described for lack of oxygen. 

 As far as KCN is concerned, Schoenbein had already observed that it 

 retards the oxidation in the tissues, and Claude Bernard and Geppert 

 confirmed this observation. For the alkaloids, W. S. Young has shown 

 that they are capable of retarding certain processes of autoxidation. 

 This accounts for the fact that the above-mentioned poisons produce 

 changes similar to those observed in the case of lack of oxygen. 



I. 



4. THE PRODUCTION OF CO 2 THROUGH ENZYMES 



It seems that organisms are pretty generally capable of producing 

 CO 2 from certain organic compounds, without the presence of free 

 oxygen. The classical case of the production of CO 2 through a process 

 of cleavage is the alcoholic fermentation of sugar under the influence 

 of yeast cells. In this case one molecule of dextrose is split into two 

 molecules of CO 2 and two of ethylalcohol. The process occurs in the 

 absence of oxygen as well as in its presence, or, according to Pasteur, 

 even better in the absence of oxygen than in its presence. The catalyzer 

 in this case is an enzyme, the zymase, which Buchner succeeded in 

 liberating from the yeast cell. This discovery is of special interest, 

 as for years it was impossible to separate this enzyme from the cell. 

 Pasteur even went so far as to maintain that the process of alcoholic 

 fermentation was of an altogether different kind from that of the inver- 

 sion of cane sugar, as the latter was due to an enzyme, soluble in water, 

 which could easily be extracted from the cell ; while this was not so in 



* Budgett, Am. Jour. Physiology, Vol. I, p. 210, 1898. 



