754 



PRINCIPLES OF SOIL MICROBIOLOGY 



found various adherents. Fred 58 found that proper concentrations of 

 ether, CS2 and CuS0 4 have a stimulative effect upon the growth of 

 lower microorganisms; even nitrification, which was at first decreased, 

 was later stimulated. CS2, in dilute solutions, was found to stimulate 

 growth of plants, including that of fungi. 59 According to Hiine, 60 small 

 doses of poisons may be directly stimulative to bacterial development. 

 The influence of antiseptics upon the development of microorganisms 

 in the soil, namely those that can be determined by the plate method, 

 is brought out by tables 84 and 85. A large increase in soluble nitro- 

 gen, as a result of treatment with CS 2 , is found both in the inoculated 



CHLOROFORM 



M/50 to M 



LARGER PROTOZOA 

 KILLED 



AMMONIA and NITRATE 

 PRODUCED 



DAYS. 



Fig. 67. Influence of different amounts of chloroform upon the bacteria, 

 protozoa and available nitrogen in the soil (from Buddin). 



and uninoculated soils. The ammonia content of the soil was found 

 to follow the curve of bacterial growth and later giving rise to nitrates. 

 CS 2 did not act alike on all soils and toward all crops. 



Russell and associates (figs. 67 and 68) attempted to correlate the de- 



68 Fred, E. B. Uber die Beschleunigung der Lebenstiitigkeit huherer und 

 niederer Pflanzen durch kleine Giftmengen. Centrbl. Bakt. II, 31: 185-245. 

 1912. 



69 Oldenbusch, C. Stimulation of plants by CS 2 . Bull. Torrey. Bot. Club., 

 49: 375-390. 1922. 



80 Hiine, Dr. Die begiinstigende Reizvvirkung kleinster Mengen von Bak- 

 teriengiften auf die Bakterienvermehrung. Centrbl. Bakt. I, Orig., 48: 135- 

 140. 1907. 



