Cells oval, single, or united in pairs, rarely in fours, never in elongated chains; imbedded in an abundant mucilage, which is very soluble in water; movements oscillatory; length of a separate cell, .00004 to .000056 in.; width, .000028 in.; length of a pair, .00008 in.; of four united, about .00012 in."

It is quite evident that the disease is one of the outer cellular bark, as the bacteria are unable to penetrate through the best cells, and can spread up or down only by working their way through the apparently solid cell walls. There being no such things as sap veins in plants, analogous to blood veins in animals, the spread of the disease from the point of attack must be comparatively slow.

Soil, situation, exposure, etc, have little or nothing to do with the disease. That some varieties are more subject to its attack than others is well known, and has been fully discussed by your society, as well as lists published of those most exempt.

Of the different modes of cultivation, the one that produces a moderate, healthy growth should be preferred to that of excessive growth. It is quite apparent that trees highly stimulated by manure, severe winter pruning, and clean cultivation are most subject to "blight." The orchards uniformly most exempt from "blight" that have come under my observation were those well cultivated in grass, i. e., the grass kept short by repeated cutting (never allowing the grass to ripen or go to seed), with occasional, at least biennial, top dressing of barn-yard manure, or other fertilizers. In short, treated like a lawn. The annual growth will be moderate, but healthy; quite different from those stimulated to excessive growth by clean cultivation and the stereotyped annual cutting back of two-thirds of last season's growth.

Remedies: Eternal vigilance and a sharp knife. Carbolic acid is extensively used to destroy bacteria; it may be diluted with 1,000 parts of water to one of the acid. Quinine is also used. Cold does not kill them, but activity ceases at or near the freezing point. Frische claims that 1230 Fahrenheit below zero will not kill them. In the adult state most bacteria are destroyed in water heated to 1500 Fahrenheit; spores have been known to survive a short immersion in boiling water.

I have often prevented the increase of poisoned parts by carefully cutting off the outer bark with a sharp knife, and applying linseed oil. This must be done very soon after the appearance of "blight."

A careful examination should be made after every warm rain, and warm nights with dew. Such examinations should be made at least once a month during the summer. Any parts showing signs of the disease should be removed immediately; if an ordinary sized limb it had better be cut off; if on the trunk or large branches, the outer bark may be peeled off and the spot covered with oil.

All diseased parts removed, branches and bark shaved off should be consigned to the fire at once. It requires close observation to detect the disease in the first stages, the bark turning black is rather a second stage; and also to make sure that the cut is below all the affected parts.

In the case of contagious diseases among animals caused by bacteria, it has been found that the bacteria may be cultivated, whereby it loses most of its poisonous qualities, and animals inoculated with it take the disease in a mild form and are ever after free from that disease.

Now let us hope that some genius will contrive a way to cultivate the species of bacteria under consideration, so that by inoculating pear trees with it they would be "blight" proof. This would open a field for a new profession - a tree doctor.

[This paper was read before the Western New York Horticultural Society.]