that it has been forced upon our attention in another and, for those immediately interested, more unpleasant way.
For the last hundred years or more, under the influence of the peculiar methods of cultivation which have been employed by our fruit-growers, various diseases have appeared from time to time in several of our important fruits, and to such an extent have some of them developed within the last ten or fifteen years that they have completely destroyed the fruit industry in some sections, and now threaten a more general annihilation of one of the most enticing and profitable occupations for the farmer. For the last hundred years we have heard of the "blight" in pear-trees, and the best records show unmistakably that the disease has been on the increase during that period. So badly is it developed in some fruit sections, as through Southern New York, that it is a matter of extreme difficulty to find a really healthy tree. For the last eighty years we have also heard of the "yellows" in peaches, and here again we find that history records a constant development of the affliction. So serious have its ravages proved that whole sections have been deprived of the very important industry of peach-culture. Not only this, but the disease is now so thoroughly established, and has come to be so much a matter of inheritance, that the life of the tree is greatly modified and even determined by it. The peach is naturally a long-lived tree, instances brought to my notice showing that it may live for upward of one hundred or more years, and, if well cared for, it will certainly produce fruit for a long period. At the present time, however, as in the great peach districts of Delaware and New Jersey, we find that, owing to the certainty of disease appearing, or the inherently weak constitution resulting from its previous operation, the period of a profitable life is limited to nine years, at the end of which time the trees are rooted out of the soil as worthless.
Twenty-five years ago the Hudson River Antwerp came into cultivation in Southern New York, and for a long time was a famous berry, and made money for those who cultivated it. Within a few years a disease has appeared, and to-day it is considered worthless to the fruit-grower. And so it is with others of our important fruits. Diseases are yearly becoming a more and more familiar foe for the horticulturist to deal with, and a great deal of alarm is felt, and with reason, lest the fruit industry in some directions be completely destroyed. Thus it is that within a few years it has become imperative that something be done, looking to the acquisition of facts which will enable us to successfully cope with these disorders, to ward them off or arrest their progress. Fortunately, the question is an important one, and so is yearly claiming more careful attention from scientific men.
Diseases arise from such a variety of causes, and are so various in their effects, that we can not judge them all from the few given as illustrations. Moreover, there seems to be such an inadequate concep-
