100 The Galls of Essex; a Contribution to a
supposed to consist of some acid injection into the plant-
tissues, at the time of oviposition, by the parent insect.
It may well be thought that the Cynipidae sting plants in a
way similar to that in which the Aculeate Hymenoptera
(ants, bees, wasps, &c.) operate upon animals, and which is
so often painfully patent to ourselves ; even the gall-gnats
(Cecidomyidae) may be similarly accredited with a kind of
stinging power without much stretch of imagination, when
reasoning from analogies. But we can hardly suppose many
of these growths to be due to the stings of the various moths,
beetles, plant-lice (Aphides), bugs, and especially mites,
which are known to produce them. Scientifically also, the
theory of a special "gallic" poison injected by the mother
gall-maker cannot stand. I am sorry to see that Sir James
Paget should foster this opinion, when he remarks:—
"We find hundreds of different forms of galls, and we may
be nearly sure that there are as many kinds of morbid
poisons produced by the gall-insects, each form answering to
a different virus."5 Mr. G. B. Buckton also writes, "It may
be noted that the injection of acrid or other juices into living
vegetable tissue by Hemiptera and other insects produces on
plants phenonema very similar to inflammation in animal
organisms. Vessels become turgid, cell-walls become thick-
ened, and abnormal growths (in vegetables often elegant
instead of monstrous) take the place of simple structures."6
In a paper read before the Linnean Society on January
21st, 1875, Dr. W. Ainslie Hollis fully examined the question
of the causative formation of galls. To this memoir I am
indebted for some of the following views and opinions of the
older writers.
Zoology and Botany as sciences may reasonably be said to
commence with Linne. It will be quite useless to examine
further back, although folk-lore is very entertaining and the
5 'An Address on Elemental Pathology, delivered in the Pathological
Section of the British Medical Association, at the annual meeting in
Cambridge, August, 1880.' By Sir James Paget. P. 23. London, 1880.
Also the 'Lancet,' October 23rd, 1880, p. 646.
6 'Monograph of the British Aphides.' By George Bowdler Buckton,
F.E.S., F.L.S., &c. London (Ray Society), vol. iii., p. 85; 1881.