GALLS 93 
twigs of the oak and hides one of her eggs in the open- 
ing : the gall arising thence; and I thought that all galls, 
glands, excrescences, etc., were never seen except on those 
branches wherein the flies had deposited their eggs; the 
galls themselves being a disease caused in the oaks by 
the fly's sting, in the same manner that we see swellings 
arise in the bodies of animals after they have been stung 
by similar insects. I was also in doubt whether the galls 
arose first, and the flies, on coming afterwards, deposited 
in them some kind of seminal fluid that, pregnant with 
procreative power, penetrated to the most remote parts, 
and fertilizing them, produced the worm. But I re- 
flected that there are many kinds of fruits and vege- 
tables, which, though protected by their rinds or pods, 
still are wormy; and I observed, also, that all ex- 
crescences constantly arise in a certain part of the 
branches, and always in young ones, appearing always 
in the veined parts, and never on the smooth surface, 
and invariably on the side of the leaf turned to the 
ground, and not on the side looking Skyward; having 
also taken into consideration that, when the leaves of 
trees on which grow vesicles or pouch-like swellings full 
of worms first bud out, they are even then covered with 
these growths, as can easily be seen, though they are 
very minute; these vesicles grow with the growth of the 
leaves, as anyone can prove to his satisfaction by ob- 
serving the excrescences on the leaves of the elm, the 
wild plum, the ilex, and the lentisk. For further ex- 
ample, the holm oak produces some bunches of flowers 
from which arise the same number of red berries, each 
of which engenders three or four worms, enclosed in a 
separate cell. The same tree produces another bunch of 
flowers, from which arise several greenish-yellow calices. 
