PLANT GKOWTH. 



437 



The fertilized vines appeared, on the whole, more vigor- 

 ous, aud the leaves, as a rule, retained their vitality longer 

 in autumn than in the case of the unfertilized ones ; they 

 escaped repeatedly a serious attack of mildew when the re- 

 mainder of the vineyard suffered with it more or less. The 

 sugar seemed to be somewhat increased in the fertilized 

 fruit of the Concord grape, and had increased one-third in 

 quantity in the wild purple grape. The increase of sugar 

 was accompanied by a marked increase in potassa, and, at 

 the same time, a remarkably reduced percentage of lime in 

 the inorganic portion of the grape. The intluence of fertili- 

 zation on the composition and the character of the fruit mani- 

 fested itself in a higher degree in the case of the native wild 

 grape than in the case of the improved variety. The results 

 of these experiments afford an additional illustration of the 

 opinion that special fertilization must be considered a factor 

 of more than ordinary importance in fruit culture. Of 

 course, sugar alone does not control the quality, yet the fact 



