510 THE HORSE. 
frequently in millers’ and brewers’ horses, which are fed upon grains, bran, 
and substances known to contain a much larger proportion of magnesian 
salts than other vegetable matters.’ Mr. Carter has detected minute por- 
tions of wheat, oats, and hay in the calculus, which therefore may be said 
to consist of two substances, viz. the vegetable and the mineral. So 
much, then, for the composition of the calculus ; now for its mechanical 
structure. Most decidedly it may be compared to an onion, layer being 
packed over layer, so as in section to present a ringed appearance. We 
may also liken it to other objects. It has lately struck me to examine 
the structure of a common cricket-ball, which combines hardness, light- 
ness, and elasticity in such an admirable way. Upon making a section, 
I found the cricket-ball to be composed of layers, one over the other, 
round a central nucleus. The layers are composed of leather, alternated 
with a vegetable fibre, the nucleus being a bit of cork. The calculus in 
the horse is formed in a similar way. The nucleus in Mr. Carter's 
specimen is a bit of flint; in a capital instance I have in my own collec- 
tion, of a common shot, about No. 5 size, which has been crushed by tho 
horse’s teeth, and subsequently swallowed ; in another instance, of a chair 
nail of brass; in another of a single oat-seed ; in another of a minute 
bit of cinder, and so on, as it seems to be absolutely necessary that these 
calculi should have a commencement—a starting point. Where is the 
school-boy who can make a gigantic snowball without beginning with 
a small lump of snow or a stone, as a nucleus upon which he builds all 
the rest ? 
“Mr. Carter seems to wonder at the weight of the specimen, 5 lbs. ; 
this is by no means a large size; in the museum of the Royal College of 
Surgeons we have a very fine collection of calculi, the largest, taken from 
the intestines of a horse, weighs no less than 17 lbs., and is about the 
size and shape of an ordinary skittle-ball. In the case where this is 
contained he will see many other specimens, cut in sections to show the 
nuclei ; he will observe that calculi also form in the intestines of the 
camel and of the elephant, and even in the wild horse, for there is a good 
specimen from the intestines of a Japanese wild horse. Stones, not true 
calculi, are sometimes found in animals, which have been actually swal- 
lowed by them, and have not been chemically formed in this walking 
laboratory. There is a case containing several pebbles—thirty in number 
—found in the stomach of a cow at Barton-under-Needwood, Burton-on- 
Trent. These stones belong to the geological formation of the neighbour- 
hood ; it is curious to see how they have been acted on by the action of 
the stomach, for they are highly glazed and polished. I have seen speci- 
mens of gravel pebbles which I took from the gizzard of an ostrich, which 
are as highly polished as an agate marble. The bird swallowed the stones 
to assist its digestion ; the cow out of a morbid appetite. I know of a 
somewhat similar instance that lately happened : A young lady was taken 
il, and died of very strange symptoms; it was subsequently ascertained 
that the stomach was quite filled with human hair, which had moulded 
itself into the shape of the interior of that organ. The poor girl had 
naturally very long and beautiful hair, and she had an unfortunate habit 
of catching the loose hairs with her lips and swallowing them ; in time 
they felted together, became a solid mass, and killed her—a warning to 
other young ladies which should not be neglected. In the lower animals 
we frequently find rolled balls of hair from the creatures licking them- 
selves. I have seen one at Bristol from a lioness; it is formed of hairs 
Ucked with her rough tongue from her cubs. Curious concretions are 
