BY R. GREIG-SMITH. 



845 



air-temperature, the water being replaced from time to time as 

 it evaporated. After this time, they were allowed to dr}' slowly, 

 while portions were taken at intervals and treated with toluene. 

 Gil bay's solution was used for the cultivation. 



'I'he experiments show that there is considerable irregularity, 

 either in the effect of the disinfectant or in the capability of 

 growth after treatment. It appears, however, that toluene has 

 little disinfecting action, when the moisture-content is lower 

 than from one-tenth to one-twentieth of the water-holding 

 capacity of the soil, and that when soils are quite moist, amoebae 

 and flagellates may not be affected to any great extent. It is 

 possible that, had nitrate hay-infusion been used instead of 

 Giltay's solution, the ratios would have been narrower. 



It appears to make no difference, whether the water is origin- 

 ally present in the soil, or is added at the time of toluening. A 

 garden-soil with 6*2 % of moisture was allowed to dry slowly in 

 the air, while portions were taken from time to time, and treated 

 with 1 % of toluene. When air-dried, the soil was moistened 

 with varying quantities of water, and treated straightway with 

 toluene. 



Garden-soil (W.H.C.=40). 



Field-soil (W.H.C.=25). 



These experiments show that, if the moisture falls below one- 

 twentieth of the water-holding capacity, one per t^ent. of toluene 



