170 Nitrogen Fixation by Yeasts 



gen. These discoveries led further to a study of other organisms 

 belonging to the groups of yeasts, molds and the higher fungi, 

 in a search for those among them which possessed the peculiar 

 physiological power to fix atmospheric nitrogen. These studies 

 have resulted in both positive and negative results frequently 

 with the same organisms in the hands of different investigators, 

 and the present status of the question is still unsettled pending 

 further evidence of the definite and constant powers of the fungi 

 mentioned to fix atmospheric nitrogen. It was therefore with 

 the double intention of making a further contribution to our 

 knowledge of the nitrogen fixing powers of some of the organisms 

 already studied as well as the study in that direction of organisms 

 which until now, so far as the writer is aware, have not been 

 experimented with, that the subjoined investigations were under- 

 taken. It was decided to make a study of the nitrogen fixing 

 powers of some of the true yeasts, "pseudo-yeasts/' 1 Mycoderma 

 varieties and some of the common molds, among them Aspergillus 

 miger, Penicillium glaucum, Botrytis cinerea and others. Before, 

 however, going into the detailed description of the experiments 

 /carried out it will be helpful for purposes of comparison to review 

 briefly the several researches, which have been carried out on the 

 nitrogen fixing powers of organisms which are the same or simi- 

 lar to those employed in my experiments. 



The investigations of Jodin 2 and Hallier 3 carried out as early 

 : as the sixties of the last century led them to believe that fungi 

 were possessed of the power to fix nitrogen. Their results and 

 opinions on this matter were not confirmed, however by Woff 

 and Zimmerman. 4 



Sestini and del Torre reported some investigations in 1876 

 which seemed to have a doubtful significance. In their communi- 

 cation they make mention, however, of a statement by Selmi in 

 which the latter attributes to the Mycoderma forms the power 

 to produce ammonia from atmospheric nitrogen in the presence 

 of nascent hydrogen. 



1 A term employed by zymologists to designate the yeast-like organisms 

 which do not form spores. 



*Compt. rend, de I'Acad. des Sci., Iv, p. 612. 



*Zeitschr. f. Parasitenkunde, i, p. 129. 



4 Abstract in Jahresbeiicht der Agrikultur Chemie, xiii-xv, p. 169 



