This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
A stray ray, reflected from the Academy Natural Sciences, in Friends' Intelligencer, brings the remark, "That, so far as he (Thomas Meehan) knew, Dr. Hoffman, who in 1876 published a paper on the subject, is the the only scientific man of note who takes ground against this view (that honey-dew is the work of insects)." Dr. John Mason Good, in his great work on the Study of Medicine, when treating of Parura mellita diabetes, has this remark, vol. v, page 349, "A similar complaint is to be traced amongst plants, though the author does not remember to have seen it noticed as such by any physiologist. What the diabetes, honey-water or honey-urine is to animals, the mel-ligo, or honey-dew, seems to be to the vegetable tribes. In both, an ordinary aqueous secretion is for the most part increased in quantity, and constantly combined with a production of saccharine matter, and in both the effect is great debility, atrophy and emaciation of the vital frame.
"The plant usually recovers, because the coldness of the winter, that puts a stop to the natural actions, puts a stop also to those that are morbid. The animal usually dies, for in him there is no such regular cessation. But in evergreen plants, which suffer no winter torpitude, the disease is almost as fatal as among animals".
The analogy is more plausible than the cause which he assigns: "The honey-dew is in general produced suddenly, by a peculiar haze or mist, apparently loaded with a specific miasm or other material, poisonous to certain kinds of plants, though innoxious to others. The leaves, and often the stems, which it affects, as it creeps along, immediately throw forth an augmented secretion from their surface, more viscid, in texture; and, as just observed, considerably impregnated with sugar".
This matter settled, the extreme fecundity of the aphides, and their fondness for saccharine food, supplies all the rest. He tells of their great destruction of the hop crop on a special occasion. Such was the case wherever a hop vine was seen in this vicinity last year. The young hops were literally covered with aphides, and utterly destroyed. I had not observed the honey-dew to precede them. It had no doubt done so. Earlier, it had been abundant on my apple trees, where most of the primary growth of leaves became diseased, crisped and fell off. The aphis was not present. While I accept the melligo on the apple leaves as a morbid vegetable secretion, I do not find it so easy to decide whether the disease is primarily seated in the foliage, and dependent on atmospherical changes, or constitutional in the general or-ganism. It must also be an interesting inquiry, how far its production is connected with the earlier processes of fructification in the same or in other contiguous plants. Dr. Good appears to take precedence of Dr. Hoffman by no less than fifty-nine years.
Please excuse the freedom.
Toughkenamon, Chester co., Pa.