FACTORS OF INCREASE 103 



vegetative and reproductive parts of the har- 

 vest as in the preceding cases. In a crop of 

 wheat (see table iii) thus treated it was 

 found, that while the total weight of straw 

 and grain w^as both as a whole and separately 

 increased by the hot water treatment, the 

 yield of grain was lessened as compared with 

 the yield of straw. 



If we turn from the statistical method of 

 demonstration and appeal to general obser- 

 vation, an overwhelming array of facts can 

 be brought to bear. 



It is a common observation that plants in 

 too rich soil run to leaves instead of fruit. 

 Every farmer knows that he can expect httle 

 or no grain from an excessively rich spot of 

 ground, although the plants grow far taller 

 and larger. The orchardist root-prunes his 

 trees to bring them into bearing, when they 

 prove to be unusually backward ; the florist 

 permits his plants to become pot bound to in- 

 duce them to flower more freely; certain 

 slow acting diseases, e. g., peach yellow, and 

 cotton rust, increase and hasten the fruiting. 

 A wide range of such general facts could be 

 cited, familiar to every one having experience 

 in such lines. In this connection Professor 

 Atkinson, of Cornell University, has called 

 attention to the longer time that elapses be- 

 fore spores are formed when certain bacteria 



