478 REPOKT OF THE SECRETAEY OF THE 



the other hand, the conditiou which will best enable any liv- 

 ing thing to resist a contagious disease, or to rally from its 

 effects when attacked, is a condition of vigorous vitality. 



Let us glance at the conditions which have long been at 

 work, tending to lower the vitality of the peach tree. In all 

 forms of life there are two tendencies, which, in certain respects, 

 are antagonistic. The one is the development of the individ- 

 ual, the other the reproduction of its species. The lower 

 we descend in the scale of life, and in proportion as the indi- 

 vidual sinks in importance, so does the reproductive tendency 

 increase. While the higher forms of life produce but one off- 

 spring, and at long intervals, the lower forms multiply by 

 thousands, and with astonishing rapidity. So also, individuals, 

 as they are lowered in vitality, become more productive. No class 

 multiplies so fast as the scrofulous or consumptive. In the 

 tree, the formation of woody fibre may be considered as repre- 

 senting this effort at the development of the individual; 

 while the physiological significance of the formation of fruit, 

 is simply an effort to reproduce its species. 



Dr. Van Mons, in the cultivation of the pear, has beautifully 

 illustrated the law that the wood-forming and fruit-producing 

 tendencies in a tree, are in inverse proportion to each other. 

 By experiments, running through more than thirty years, he 

 has shown that by checking the vigor of growth, the produc- 

 tion of fruit was accelerated, so that seedling pears, which 

 naturally would not fruit before thirty years of age, were made 

 to fruit at four. 



It seems to me, that in the peach we have pushed the fruit- 

 producing tendency to a dangerous excess; and we can 

 recover a healthy equilibrium only by favoring the wood-form- 

 ing tendency, at the expense of present fruitfulness. 



The characteristic of the peach, as now grown in the United 

 States, is a rapid and precarious development. If we consider 

 the rapidity of its growth, as compared with other fruit trees 

 growing under the same circumstances, we shall see that it 



