Stka.m Stkkii.ization on Water-Soluble Matter in Soils. 263 



Effect of an infusion of unsteamed soil on a steamed soil 

 As the process of steaming, as performed in these experiments, com- 

 pletely sterilized the soil, it was concluded to try the effect of reinocu- 

 lating the soil so treated with some of the unsteamed soil to see whether 

 the organisms thus introduced would cause a more rapid recovery from 

 the effects of steaming than otherwise took place. One hundred grams 

 of unsteamed soil were shaken up with 250 c.c. of sterile water, allowed 

 to stand 20 minutes, and the supernatant infusion (about 200 c.c.) 

 containing some soil in suspension was added to the steamed soil. 



Fig. 72 — Effect oj adding an infusion of unsterilised sod to a sterilized soil as indi- 

 cated by a crop of wheat 44 days after planting 



Pot 32 — Soil No. 5 untreated 

 Pot j6 — Soil No. 5 sterilized 

 Pot 54 — Soil No. 5 sterilized and treated with an 

 infusion of the same soil not sterilized 



Soil No. 7 was placed in pots, four of which were steamed and two not 

 steamed. Two of the steamed pots were treated with the infusion and two 

 were not. One of each of the two pots receiving the same treatment was 

 planted with wheat. The following are the pot numbers and treatments : 



Pot 63 steamed, not planted. 

 Pot 64 steamed and planted. 



Pot 65 steamed + infusion of unsteamed soil, not planted. 

 Pot 66 steamed + infusion of unsteamed soil and planted. 

 Pot 67 unsteamed, not planted. 

 Pot 68 unsteamed and planted. 



Fifty seeds were planted on March 22 in each of the planted pots. 

 Following are the records of germination: 



