Journal of Proceedings. lxix
The President, at the conclusion of the paper, said he was sure all the
members of the Club would agree with him that they were much indebted
to their Vice-President for his admirable treatment of a subject which
presented so many points of interest to them all, and one which Mr.
Fitch had for many years made a special study. In addition to the
important list of the galls of their county, the author had given a most
valuable introduction containing a resume of the different theories of the
cause of galls which had been propounded ; and he (the President) felt
sure that a subject which appealed to so many different classes of their
members—to their zoologists, botanists, and general biologists—would be
warmly taken up. The President thought that the best compliment they
could pay to Mr. Fitch would be to discuss the subject thoroughly; and
in inviting observations upon it he felt confident that the author would
be only too glad to reply to any questions that might be put to him.
A long discussion then took place with reference to various points in the
history of galls touched upon in the paper.
Dr. Pearce took exception to Sir James Paget's opinion that there was
an analogy between the growth of galls on plants and the morbid pro-
cesses exhibited in many diseases of the human subject, but before
considering that point, he wished, as a new member of the Club, to
express the pleasure with which he had listened to Mr. Fitch's paper; he
had never heard a more complete bringing together of a multitude of facts
and observations than that which the essayist had presented to them that
night. Returning to the allusion in the paper to the inoculation of the
human system with the several "viruses"—such as variola, vaccina,
cancer, syphilis, and other inoculable and constitutional diseases—he
understood the essayist to state that the formation of galls in the vege-
table kingdom bore a resemblance to the action of the said viruses in the
animal system. In his (Dr. Pearce's) opinion a distinct line must be
drawn between the two classes of phenomena ; and while there was some
dispute amongst biologists as to whether galls were due to the mechanical
irritation of the egg, or to the introduction with it of some stimulating
fluid by the insect which tended to produce the galls, there was still no
real analogy between their production and the results following an inocu-
tion with animal virus. On a tree the egg of a gall insect might be
immediately productive of a morbid growth—a gall limited to a given
spot, and not affecting the life or disturbing the general condition of the
plant. In the case of inoculating, whether with variola (small-pox) or
vaccina (cow-pox), a process of fermentation is set up, permeating and
affecting the whole system—giving evidence of its existence after the lapse
of a certain fixed number of days, by the appearance in vaccina of a
vesicle at the seat of inoculation, or, as in the case of variola, developing
on every part of the surface of the body hundreds of vesicles, which ulti-
mately become pustules. He further remarked that there did not reason-
ably appear to be a resemblance between galls in the vegetable kingdom
and certain skin diseases incident to the genus homo, children more