﻿i 9 i6] KOPELOFF, LINT, COLEMAN— SOIL FUNGI 249 



which is to be noted from this experiment, is that despite the fact 

 that media were furnished for the growth of fungi none was evident, 

 even after 30 days' incubation. 



From the observation of the poured plate cultures of series 2, 

 made from the same 3-day old culture as series 1, it was noted that 

 fungi appeared after 4 days upon 3 out of 10 plates; namely, 

 Cook's no. II, Lipman and Brown's synthetic, and raisin agar. 

 The predominating fungi were species of Penicillium, Alter naria, 

 and Fusarium. On the poured plate cultures of series 3, inocu- 

 lated with the solution in the cavities of the agar plates in series 1 , 

 no fungi developed. This experiment was repeated and corrob- 

 orated the previous results. Thus it appears that although fungi 

 were present in the original culture, the process of high dilution was 

 responsible for their elimination in the specially prepared cavity 

 on the agar plates in series 1 . 



Another method with the same object in view, namely, the 

 separation of fungi from bacteria and protozoa, was employed, the 

 procedure of which was as follows: Poured plate cultures of the 

 10 different media (as before) were made from the same 3 -day old 

 culture of soil extract known to contain numbers of bacteria, 

 protozoa, and fungi, and the plates were watched carefully through- 

 out the period of one week's incubation for the appearance of 

 any fungi. As soon as their presence was discerned, the fungous 

 growths were removed with a sterile scalpel. At the end of one 

 week, at which time it was reasonably certain that the fungi had 

 ample opportunity to develop, a portion of the agar, about 1 sq. in. 

 in size, was removed with a sterile scalpel from each of the 10 plates, 

 placed in 50 cc. of soil extract, and the flask thoroughly shaken to 

 disintegrate the agar. For 4 days a microscopic observation was 

 made and a few small flagellates and small ciliates were discovered 

 on the preparation from raisin agar, and a few small ciliates and 

 numerous small flagellates on the apple agar. No large ciliates 

 were noted. 



Summary 



1. The dilution method followed by the peculiar manner of 

 plating as outlined makes it possible to separate fungi from bacteria 

 and protozoa. 



