102 THE SPIRIT OF THE SOIL 



animals recovered when their diet of white bread 

 was replaced by wholemeal bread. To describe it 

 in detail would take up too much space, and to do 

 so is the less necessary because it formed the basis 

 of the campaign instituted a few years ago in favour 

 of " standard bread." The fact that I wish to 

 emphasize is that vitamines are as essential to 

 growth as they are to health ; in fact they are more 

 so, as in diet where they are abundant the normal 

 rate of growth is stimulated. So much is this the 

 case that it has even been suggested that they may 

 be responsible for tumour growth, and that the 

 formation of tumours might be checked by the 

 elimination from the diet of the substances exciting 

 growth. 



In the course of the experiments made with 

 bacterized peat or humogen some very surprising 

 results were obtained. In the first instance, in a 

 whole series of experiments conducted at Kew 

 Gardens and at the Chelsea Physic Garden during 

 the summer of 1913, on various pot plants wheat, 

 barley, oats, maize, salvia, fuchsia, carnation, 

 primula, etc. it became evident that the bacterized 

 peat possessed a certain growth-stimulating property 

 that could not be accounted for by any known 

 manurial constituents present . Further experiments 

 showed that the stimulating substance was soluble 

 in water and effective in very minute quantities. 

 Dr. Rosenheim of King's College, in an experiment 

 with seedlings of Primula malacoides, potted up in 

 loam, leaf mould, and sand, found that plants 

 watered twice with the water extract of only 



