BY R. GREIG-SMITH. 



733 



After the week's storage in the laboratory, the soil did not 

 give so strongly toxic an extract. After still another week, the 

 toxicity had disappeared, and the extract was nutritive. 



Experiment xi. 



In the experiment, the yeasts grew upon the same plates with 

 soil-bacteria, and were distinguished by the small size of their 

 colonies. They were very numerous, being in the ratio of about 

 250 : 1 of the soil-bacteria. 



The results of the foregoing experiments show that the chloro- 

 form does act as a stimulant in soil-extracts, and we are justified 

 in concluding that it will also act in this manner in soil-moisture 

 Its persistence in the soil after treatment, combined with its 

 action in soil-extracts, argues in favour of the stimulation-theory 

 that the great increase in the bacterial numbers, following treat- 

 ment of a soil with chloroform, is due in part to the stimulation 

 of the bacteria by small doses of the disinfectant retained by the 

 soil. 



