1908] HASSELBRING— ASSIMILATION OF PENICILLIUM 189 



95 C. The reaction- is due, as Nef 11 has shown, to the absorption 



of water by the bivalent carbon of the ethylidene particles. The 



reaction may be represented as follows. The dissociation of ethyl 



sulfuric acid takes place thus : 



-H 

 CH 3 CH 2 OS0 2 OH^CH 3 CH=:+-OS0 2 OH 



The sulfuric acid is regenerated and reacts with more alcohol to 

 give ethyl sulfuric acid, or ethyl sulfate, while the ethylidene decom- 

 poses water to form ether thus : 



CH 3 CH<q 

 CH 3 CH<tt 



If, in the first steps of assimilation, alcohol enters into combina- 

 tion with some substance of the protoplasm to form an unknown 

 compound, represented by CH 2 CH=Ppm, then we should expect 

 substances which increase ethylidene dissociation to affect the rapidity 

 of assimilation. It is immaterial whether the alcohol is first elaborated 

 into sugar, glycerin, or some other substance, before it becomes a part 

 of the protoplasm, or whether it is directly taken up by the permanent 

 constituents of the cell. In either case it must combine with some 

 substance of the cell, and this combination must be regarded as the 

 first step in assimilation. 



An examination of the cultures (tables II, III) shows an increase 

 in growth due to the addition of sulfuric acid, which, even in dilute 

 solutions, would to some extent combine with alcohol and dissociate 

 into ethylidene ; but an equal increase is obtained by the addition of 

 hydrochloric acid, and nitric acid shows an even greater increase in 

 most cases; yet neither hydrochloric nor nitric acid combines with 

 alcohol when mixed with it. This would indicate that stimulation 

 by the acids is not due to any dissociating effect on the alcohol. Fur- 

 thermore, if assimilation took place by direct combination of ethyli- 

 dene with some substance of the cell, then bodies which dissociate 

 very easily should be most rapidly assimilated. We find, however, 

 that potassium ethyl sulfate and ethyl nitrate, which dissociate to a 

 high degree, are valueless as sources of carbon when given alone, and 

 in all probability cannot even be utilized by means of energy derived 



11 Nef, J. U., Dissociationsvorgange bei den Alkylathern der Salpetersaure, der 

 Schwefelsaure, und der Halogenwasserstoffsauren. Liebig's Annalen 318: 1-57. 1901. 



