When noticing Prof. Arthur's treatise on blight in the pear, we noted that much of the hesitation that we had in accepting conclusions of those who had heretofore experimented came from an uncertainty as to whether we all understood each other by the term " blights." There are undoubtedly many distinct diseases or forms of diseases that might be called " blights," but the authors of treatises speak of "Pear blight" as if there was one, only one, thing to be discussed.

Now, what we know as "fire blight" is that sudden disease, which seems to destroy immense branches, apparently in a few hours. When the branch is examined, however, it is evident that the seat of the disease is at the base of the dead branch. The wood when shaved is found brown and dry for the space of an inch or more in length, and extending round the branch, apparently girdling it. This portion has a well-defined line. When we shave the wood above this line it is not brown, but of that yellowish green tint which branches have when they die from drying up. There is not the possibility of a doubt that the seat of the trouble is in that limited spot. But we do not find that any of the treatises make any special note whatever of this fact.

Just now we recur to this matter through some correspondence of a more than usually intelligent character between Dr. Anderson and Col. Leigh-ton, the well-known Pear grower of Norfolk, Va., in the Cornucopia of that city.

Dr. Anderson, an expert microscopist, follows the disease as it progresses through all its stages, and finds no bacteria until after fermentation has begun; and Col. Leighton identifies the appearance of the disease in the "twigs" with the occurrence of a great extreme in temperature. This may be a means of stirring the "cause" into activity, but can scarcely be considered the cause itself.

Though, from analogy, we feel that low microscopic organisms, as has been explained by Professors Arthur and Burrill, must be closely connected with all these different Pear "blights," we have to confess that the demonstration has not been made as clear to our mind as we should like it to be.