102 LIVING PLANTS 



Effect of 



as increasing the fertility of the soil. It is a 

 method of giving the plants a greater supply 

 of nutriment, whereby they grow larger and 

 yield more. If the principle just stated holds 

 soil fertUity true, however, the increase will be greater 

 proportionally for the stems, leaves and roots 

 than for the seeds and fruits. The data pro- 

 vided by Latta from experiments conducted 

 in Indiana bear this out. Wheat grown 

 u])on fertilized and unfertilized areas, averag- 

 ing the results of three seasons, 1889-91, 

 showed a decided gain in both straw and 

 grain due to the richer soil ; but upon exam- 

 ining into the relative increase of straw and 

 grain, it is very evident that while the increase 

 in yield of grain was considerable, it was by 

 no means so great as the increase of straw, 

 and that the proportion of straw to grain 

 was, in spite of the increased yield, in reality 

 lessened. (See table i., page 116.) Essentially 

 the same results are evident in data obtained 

 by Caldwell in Pennsylvania with corn, aver- 

 aging the results of ten A^ears, 1881-90, 

 (omitting 1887, the crop being destroyed by 

 insects). (See table ii.) 



A very different method of increasing 3'ield 

 is the treatment of seed grain before sowing 

 to a short bath in hot water. It is especially 

 interesting to find that this method develops 

 the same reciprocal relations between the 



