Some ten years ago, the rapid increase of an affection in our choice pears, which caused the fruit to become cracked and spotted, attracted the attention of cultivators to the probable cause of the deteri--oration. Various and vague were the conjectures which were hazarded by those who do not wish to be found unable to explain any horticultural problem, however abstruse. After some experimental attempts, it was finally admitted, though not without reluctance on the part of some who had committed themselves to certain opinions, that the cracking of the fruit of such varieties as the "White Doyenne" (or Virgalieu) is caused by the attack of a parasitic vegetable growth entering the tissues of the leaf and fruit, and known as a species of fungus. Gradually other maladies, attacking plants and trees, were found to be of the same nature and to belong to the same order of vegetable growth.

Latterly, much has been written and suggested on the subject of the diseases which infest the grape in vineyard culture; but we meet unfortunately with the same vague generalization on this branch of vegetable pathology which was current on the subject of the pear. The object of the writer of this communication is to ask if there is any definite means within the reach of American cultivators to ascertain, with some degree of certainty, whether the opinions respecting the diseases which are so commonly referred to as infesting the grape, are worthy of the attention of those interested in the matter? It is presumed that this is a legitimate inquiry in a magazine like the old Horticulturist, which has done so much in times past to elucidate the difficult points of culture.

Furthermore, it appears to be within the scope of some of the numerous organizations throughout the country, devoted to the promotion of fruit culture, to take note of the want of reliable precise knowledge on the subject of such diseases as the "rot" or "spot" in the grape.

The disease known as "black knot" has, after much discussion and variance of opinion, been accepted by many as a form of parasitic fungus, and an article in the Journal of Horticulture speaks of it as such, and describes the identical species to which it is assigned, without any apparent hesitation. We want a similar and equally pronounced statement as regards the "spot," which is so common on the berries of our grapes. If it be a fungus, the mycologist can readily determine the fact. In conclusion, permit me to remark that in view of the great interests embarked in grape culture, it would be worth the attention of the agricultural authorities at Washington to invest a little of the public funds in a good microscope and a machine to make some accurate observations with the same. I hope no unfair insinuations will be offered as to the motives for this suggestion.