Among the numerous experiments, relating to the diseases of plants, which have been performed at the Station, those on pear blight have excited the most interest. The first case of blight noticed in this vicinity was on a pear tree in a neighbor's yard, July 11, and on July 26, a small branch of quince in the Station garden was found blighted. These were both promptly destroyed. No other case of spontaneous occurrence of the disease has been observed within a mile or more of the Station. It has, however, appeared in considerable virulence among the pears and quinces in some localities in this region.

This seemed a most favorable opportunity of investigating the infectious nature of the disease, and accordingly on July 16, a pear orchard was visited and some of the diseased branches secured. Among these was one with viscid, yellowish drops exuding from the stem. With a needle a puncture was made about an inch from the extremity of several branches of a pear tree in the garden, and a very little of this excretion inserted. It was applied in the same manner to some terminal leaves, but a difficulty in manipulation rendered the result doubtful, for the excretion being very sticky and the leaf thin, it was not easy to remove it from the needle and insure its remaining in the wound. In from six to eight days, every branch inoculated showed unmistakable signs of the blight. The bark turned brown and then blackish about the puncture, the color extending gradually through the stem, passing upwards toward the end of the branch much faster than dowi-wards or around the branch. On the ninth day most of the wounds exuded some of the same viscid fluid which was used in the first place. They were all removed on the thirteenth day to prevent the disease securing any permanent hold on the tree.

Most of the infected branches were blackened for a foot or more, and all the tender young leaves as well, all being thoroughly dead. It was noticeable that the full grown leaves were rarely affected, and mostly remained green up to the time of the removal of the branch. Only one of the inoculated leaves became infected, and this was a young, tender one. The disease spread to the stem, and worked the same as in the other cases.

At the same time, a portion of the same virus was applied to two young apple branches. Both showed the disease in eight days. It spread gradually until on the thirteenth day about two inches from the apex was quite dead and dry, and the branches were removed.

On July 24th an inch or so of diseased pear stem was sliced up in a watch glass half full of water, and after stirring about, the chips were all removed, which left the water slightly milky. This was used to inoculate with, by making a puncture with a pin and adding a small drop from the watch glass. It was applied to the branches of several kinds of fruit, but sufficient time has not elapsed at this writing to show results, except in the case of a very young branch of June berry {Amelanchier Canadensis) about six inches long, which showed unmistakable signs of blight on the sixth day. But the most remarkable results yet secured, were gotten by inoculating the fruit of Bartlett pear with this watery infusion. On the sixth day they were all blackened for some distance around the point of inoculation and exuding a copious flow of yellowish fluid which ran down the side and dropped on the ground. In fact, each was a great running sore. Upon cutting open the pears, they were found to be discolored almost throughout their interior.

Inoculation at the same time on quince fruits, showed the disease in seven days, but without any exudation, and upon cutting them open, only about one-fourth the interior was affected.

We may make the following general statements which the experiments so far tried (some sixty in all) fully sustain. The disease known as pear blight is infectious, and may be transmitted from one tree to another by inoculation. It is not confined to the pear but may attack other pomaceous fruits, as the apple, quince, English hawthorne, and June berry. It is more active, and progresses most rapidly upon young and succulent portions of the tree.

Under the microscope any bit of diseased tissue shows inconceivable myriads of minute bacteria which fill the water of the slide in which it is mounted, like a cloud. It is, therefore, not necessary to depend on external appearances in order to determine the progress of the disease in a branch, for the microscope will decide with absolute certainty. There can not be a rational doubt that the bacteria are the cause of the disease.

Experiments are now being tried to determine the mode by which the disease is naturally propagated.

Director N Y. Exp. Station, Geneva, N. Y.