732 CONTRIBUTIONS TO OUR KNOWLEDGE OP SOIL-FERTILITY, xiv., 



tests made at the same time. In the next experiment, we have 

 a different condition. 



Experiment vii. 



Soil-extract containing chloroform 

 in parts per million. 



None 



16 

 165 



Growth of 



bacteria from a 

 raw soil. 



100 



106 



5 



Bac. prodigio.sut. 



100 

 191 

 170 



This extract was anomalous, inasmuch as it was toxic to the 

 soil-bacteria, and nutritive to Bac. prodiyiosus. The great re- 

 duction of the bacteria, in the test with 165 parts of chloroform 

 per million, suggests that the toxins of the extract may behave 

 like chloroform, and be stimulative in small doses, and toxic in 

 large doses. In this experiment, the soil-bacteria were obtained 

 from a raw soil, while, in all the other experiments, they were 

 got from a soil which had previously been chloi'oformed. 



EXPKRIMKNT Viii. 



Soil-extract containing chloroform 

 in parts per million. 



Growth of Bac. prodigiosus. 



None 



17 

 170 



100 

 100 

 137 



The extract was slightly toxic. 



Experiment ix. 



This soil was strongly toxic, and was again used a week later 

 in the following. 



