﻿HARDER— BACTERIA 



One set was kept at room temperature and the other set was placed 

 outside, subject to atmospheric temperatures. 



Six jars (3 for each set) of glazed earthenware, holding about 

 1850-1900 gm. of soil, were used. These were filled with soil 

 prepared as follows: nos. 1 and 2, Miami silt loam containing 23 

 per cent moisture; nos. 3 and 4, Miami silt loam containing 23 per 

 cent moisture and 1 per cent dextrose; and nos. 5 and 6, Miami 

 silt loam containing 28 per cent moisture. 



The soil was thoroughly mixed and the moisture raised to the 

 proper amount, care being taken to secure a uniform moisture con- 

 tent throughout the sample. Muslin was tied over the tops of 

 the jars, which allowed free access of air but which excluded dust. 

 Jars 2, 4, and 6 then were placed outside of a window, and pro- 

 tected from rain and snow by a large bell jar which allowed free 

 circulation of the air. Jars 1, 3, and 5 were kept in a room at an 

 average temperature of about 25 0 C. The jars were left untouched 

 for a period of 18 days (February 16-March 6). The average 

 daily temperatures for this period which affected the outside jars 

 are shown in graph 2. 



At the end of the period an average 20 gm. sample was taken 

 from each of the jars and treated in the same way as the field soil 

 samples previously described. Plates poured with Heyden Xahr- 

 stoff agar and counted after 8 days gave the results indicated in 









° C plate e * SPer 







23 per centH 2 0 



15.80 

 17-48 



261 

 155 



5,471,994 

 5,548,800 



28,491,543 



18,089,275 

 6,609,167 

 6,073,131 





:iP-runi IJ.O (frozen'. 

 23 per cent H 2 Oi per cent 





cent H 2 0 1 per cent 

 - [H-r ,mt if O 





28 per cent H,() (frozen! . 



It should be noted that in the cases where the soil was kept in 

 the room, the evaporation was much more rapid than in the soils 



