1908] HASSELBRING— ASSIMILATION OF PENICILLIUM 179 



to their assimilation by the molds, it was deemed possible to throw 

 some light on the mechanism of their assimilation. The simpler 

 compounds are most suitable for studies of this nature; first, because 

 their reactions are well understood, and second, because it is known 

 that the complex compounds, such as polysaccharides, glucosides, 

 and certainly in some cases even the hexoses, undergo decomposition 

 before they are taken into the cell. 8 The solution of the mode of 

 assimilation of the simpler compounds will therefore enable us to 

 approach an interpretation of this process with the more complex 

 compounds. 



Cultures were made in 20o cc flasks, of the Erlenmeyer form, 

 loosely stoppered with cotton to permit the free exchange of air. In each 

 flask 5o cc of the culture medium were used. The mineral solution 

 was first put into the flasks and sterilized for 20 minutes in flowing 

 steam, after which the organic solution was added. The concen- 

 tration of all the substances given is the final concentration after the 

 addition of the organic solution, without allowing, however for error 

 caused by evaporation in the sterilizer, which averaged a little less 

 than o.5<? m per flask. In cases where acid was added the error 

 caused by this addition was also not considered. These two errors 

 compensated each other. Moreover, it was found that much greater 

 differences than these produced no effect on the growth of the fungus, 

 and a variation in the concentration is furthermore unavoidable on 

 account of a slight evaporation in the incubator, which could not be 

 prevented. The cultures were grown in an electrically regulated and 

 electrically heated incubator, which permitted the maintenance of a 

 constant temperature of 28 C. The duration of the cultures, except 

 where noted, was 10 days. 



Considerable effort was made to work out the best method for 

 inoculating the flasks. On account of some observations of Duclaux, 9 

 indicating that some media which were suitable for nourishing 



8 Puriewitsch, K., Uebcr die Spaltung der Glycoside durch die Schimmelpilze. 

 Ber. Deutsch. Bot. Gesells. 16:368-377. 1898. 



Brunstein, A., Ueber Spaltungen von Glycosiden durch Schimmelpilze. Beih. 

 Bot. Centralbl. 10:1-50. 1901. 



Kohnstamm, P., Amylolytische, glycosidspaltende, proteolytische und cellulose- 

 loscnde Fermente in holzebewohnenden Pilzen. Ibid. 10:90-121. 



9 Duclaux, E., Sur la nutrition intracellulaire. Ann. Inst. Pasteur 3:97-112. 



