often has upon a plant is due to the fact that the nutriment which it 

 absorbs and assimilates during the summer and autumn is nearly all 

 utilized in the production of fruit, and little is stored for use in the fol- 

 lowing spring. The spring growth of a plant is all due to this reserve 

 food, and is the weaker the less of this reserve it has to draw upon. 

 Usually a year of heavy bearing is followed by a year of light bearing, 

 during which the plant is able to recuperate by utilizing the food 

 assimilated during that year for building up its vegetative organs and 

 for replenishing its depleted reserve. During the season following the 

 heavy crop of 1896, however, the weather conditions were evidently such 

 as to force the vines to expend all their resources in the production of 

 the phenomenally large crop of 1897. How exceptionally large this 

 crop was upon the vines which are now dying is not quite indicated by 

 the table above, which includes the crop from all varieties and ages of 

 vines. The crop on the old vines of heavy-bearing varieties which are 

 now dead was doubtless much in excess of the indicated average. At 

 the same time that this severe drain was being made upon them there 

 was a shortage of over four inches in the annual rainfall. It is practi- 

 cally certain, therefore, that these vines were obliged to start the year 

 1898 with empty storehouses, and the rainfall of that year being just 

 half the normal, the vines not only bore very little, but were unable to 

 obtain nutriment sufficient to satisfy their vegetative needs and to nour- 

 ish their permanent organs roots, stems, and canes. 



The next year, 1899, therefore, they commenced to fail and some of 

 them to die. In 1900 still more died, while in 1901, the present year, 

 the largest mortality of all occurred. It is, perhaps, not quite clear 

 why the mortality should be greatest in the later years when the defi- 

 ciency of rain was less than in 1898, the year of the greatest drought. 

 It should be remembered, however, that a lack of water may affect a 

 plant in two ways: If it occurs at a time when the plant is in vigorous 

 growth and full leaf the plant is injured or killed by diminution of the 

 amount of water in its cells and tissues, due to the excess of evaporation 

 from the leaves over the absorption by the root hairs. In this case the 

 plant dies of thirst and dies suddenly at the time of the drought. If 

 there is, on the contrary, a chronic deficiency of water in the soil, com- 

 mencing in the winter before the plant commences to grow, the result 

 is simply a small, weak growth of foliage, insufficient to supply food for 

 the needs of the stem and roots. The roots thus having a restricted 

 food-supply fail to grow with normal vigor and in turn fail to supply 

 the rest of the plant with the soil nutrients which it is their function to 

 collect. We have in this latter case not so much injury from thirst as 

 gradual starvation, which is slower in its action and probably, when 

 several dry seasons follow each other, cumulative, as the reserve food- 

 supply becomes each year more depleted until the plant dies. 



