94 THE SPIRIT OF THE SOIL 



produces humate from the insoluble potash and 

 phosphate are very important, for they point out a 

 way of cheaply converting the inert plant foods of the 

 soil into more active and available forms. Considera- 

 tion of these facts makes it understandable why the 

 application of organic manures has such good effects." 

 In the course of experiments made with bacterized 

 peat on the growth of plants some very remarkable 

 effects were noted. The plants which were treated 

 with the material exhibited a characteristically 

 marked root development, they frequently, almost 

 normally, matured at an earlier stage, and they were 

 generally more robust than those which had not 

 received the bacterized peat. When it is remem- 

 bered that these plants were being grown against 

 others which were receiving what the growers 

 regarded after long experience as the fertilizers best 

 suited to their requirements, it is clear that the 

 increased vigour of the plant could not be due to the 

 organic material known to be in the peat, nor to the 

 phosphates and potash that had become available, 

 nor even to the lavish supply of nitrogenous foods 

 derived from the air. The hypothesis was formed 

 that the treated peat might perhaps be rich in 

 accessory food bodies similar to the vitamines that 

 in recent years have been found to be essential to 

 animal growth. Experiments have now been in 

 progress on this subject for over two years, and the 

 accuracy of the hypothesis either in its present form, 

 or in some closely similar form, may be regarded as 

 established. As the subject is so novel, so striking, 

 and of such fundamental importance, certainly in 





