522 Recent Advances in Agricultural Science. [May 24, 



plants. Heating- the soil to the temperature of boiling water for two 

 hours will double its productivity, and such a process has been found 

 to be commercially profitable in the case of greenhouse soils. The 

 market growers of cucumbers and tomatoes make up an exceptionally 

 rich soil of virgin loam and stable manure, but in a few years such 

 soil, while still enormously rich on analysis, becomes incapable of grow- 

 ing a profitable crop. The partial sterilization processes of which I 

 have been speaking restore and even enhance its fertility by eliminat- 

 ing the injurious organisms, and we learn from the detailed results 

 that after such treatment a much larger percentage of the soil-nitrogen 

 is recoverable in the crop than normally prevails in untreated soil. At 

 present the processes have not been extended to the open field, but 

 progress is being made in that direction, and give some promise of a 

 method by which ultimately the unseen fauna and flora of the soil 

 will be domesticated, the useful races encouraged, and the noxious 

 repressed, just as the larger flora and fauna have been reduced to our 

 service since the days when primitive man first turned from hunting 

 to ay^riculture. 



[A. 1). H.] 



