AMENTIFERE. 155 
In the buds at the ends of the branches and shoots of this tree the female makes 
a puncture with her ovipositor and deposits her egg. An excrescence or gall is soon 
formed, within which the larva is developed. As soon as the larva is produced, 
it eats its way out. In these nuts we find a little circular hole, leading to a small 
canal which passes to the centre of the gall. But in those galls in which the insect 
has not put off its pupa state, we find neither an external hole nor an internal canal. 
These latter nuts are called “blue galls,” and are most esteemed, and are the produce 
of the first gathering. The galls from which the fly has escaped are called “white galls,” 
and are of inferior quality, containing less of the astringent principle than the blue galls, 
in the proportion of two to three. The white and blue galls are usually imported in 
about equal proportions, and are then called “ galls in sorts.” The British oak does 
not yield galls of such powerful qualities as those of Quercus infectoria, but of late years 
a species of cynips has infested our oak-trees, and has produced gall-nuts in very 
remarkable quantities. Any observer may see them in our hedgerows, on our oak-trees, 
in almost every field. They are about the size of a hazel-nut, and quite smooth, and 
probably, if collected carefully, might be utilised in the same manner as the foreign 
gall-nuts. We too often overlook our native productions for those of distant shores. 
The excrescences found on oak branches, commonly known as “ oak-apples,” are a 
kind of gall, and are produced in the same manner as the gall-nut, by the puncture of 
aninsect. They are astringent, and may be used for the same purposes in the arts as 
the gall-nut. The oak-apples are much sought for on the 29th of May, the anniversary 
of the Restoration of King Charles II., and commonly known as “ oak-apple day,” 
in allusion to the fact of the royal fugitive having taken shelter in an oak. In the time 
of Gerard the oak-apples were consulted by the superstitious as auguries. He says: 
“The oke-apples being broken in sunder about the time of their withering, doe fore- 
shew the sequell of the yeare; as the expert Kentish husbandmen have observed by 
the living things found in them; as, if they find an ant, they foretell plenty of graine 
to ensue; if a white worm, like a gentile or maggot, they prognosticate murren of 
beasts and eattele; if a spider, then (say they) we shall have a pestilence, or some 
such like sickenesse to follow amongst men. These things the learned also have 
observed and noted; for Matthiolus, writing upon Dioscorides, saith that, before they 
have a hole through them, they containe in them either a flie, a spider, or a worme; if 
a flie, then warre insucth; if a creeping worme, then scarcitie of victuals ; if arunning 
spider, then followeth great sickenesse and mortalitie.” Galls are not of use in 
tanning, as is the bark of the oak-tree, for the astringent principle they contain is 
gallic acid, and not tannic acid, which is alone useful in the process of tanning. 
Tannic acid is converted into gallic acid by exposure to moisture and the atmosphere, 
and this latter substance forms an insoluble precipitate with the gelatine of the hides 
before they are tanned, and will not combine with the hide at all or convert it into 
leather. The tannic acid of the oak-tree seems to be changed into gallic acid by the 
attacks of the little insects which produce the galls; at all events, the chemical 
substance which they contain is always known as gallic acid. This material is used 
largely in medicine as an astringent, both internally and as a topical agent. It is 
very useful to restrain hemorrhage, and as a gargle. This acid has the property of 
forming an intensely black salt, and is used in the production of black dyes for 
woollen cloth, calicoes, and other articles. It is also employed largely in making 
writing ink and in photography. When gallic acid is heated to 410 degrees Farenheit, 
pyrogallic acid is formed, and for many purposes, such as photography, this condition 
is preferable. 
Beside the excrescences already noticed, the oak-tree is subject to several others. 
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