1908] HASSELBRINC— ASSIMILATION OF PENICILLIUM igi 



to the aldehyde. This would account for the greater ease of assimi- 

 lation of alcohol, since the oxidation of alcohol takes place more 

 readily than the reduction of acetic acid. 



The cultures of acetic acid and potassium acetate require no dis- 

 cussion, since it is evident, especially from the acetate cultures, that 

 it is the acetate ion that is assimilated. This ion was assimilated, 

 so far as could be determined, with much more difficulty than alcohol, 

 which would be in accord with the belief that the acid must be reduced 

 to aldehyde. 



INCIDENTAL OBSERVATIONS 



As in any long series of cultures, some facts were observed in this 

 study, which, while not directly concerned with the work, may be of 

 sufficient interest to be worth noting. 



Duclaux is responsible for the belief, current in textbooks, that 

 some substances which permit vigorous growth of mycelia are not 

 suitable for the germination of spores. Alcohol is one of the substances 

 mentioned by him. Contrary to this statement, it was found that 

 alcohol was not only favorable for growth, but also permitted abundant 

 germination of spores. From the preliminary cultures it seems prob- 

 able that all concentrations which will permit growth will also permit 

 germination. 



In many other instances substances failed to allow mycelia to 

 develop and yet were not. detrimental to germination, e. g., C 2 H s KS0 4 . 

 This whole subject deserves further investigation, with careful study 

 of the effect of different concentrations on growth and germination. 



An interesting observation was made on the alcohol cultures, 

 namely, that none of them produced spores during the growth of the 

 cultures. It is difficult at present to offer an explanation of this fact. 

 The fungus grew more vigorously in the alcohol cultures than in any 

 others, and as far as could be observed all the external conditions 

 necessary for the production of spores were present. The mycelia 

 formed dense white mats on the culture liquid, and innumerable 

 hyphae grew into the air — a condition which usually leads to the pro- 

 duction of spores — yet none of the aerial hyphae bore spores. It 

 would seem as if this strain of Penicillium was unable to manufacture 

 all of the compounds necessary for spore formation from alcohol alone ; 



