1816.} Membranous Bodies of Animals. 498 
Alobert, in his Precis Pratique et Theoretique sur les Maladies dé 
la Peau, Paris, 1810, tom.i., p. 344, Art. VIJI., had published 
two analyses of herpetic eruptions, and it gave me great pleasure to 
see that they completely coincided with my own. He discovered an 
uncombined acid in the scales, which he showed to be phosphorie 
acid. In the leprous part he found no uncombined acid, but car- 
bonate of lime. 
Iii. Nails. 
The nails exhibit nearly the same properties as the epidermis. 
They consist of the same materials, scarcely differing in their pro= 
portions. The insoluble portion possesses the characters of indurated 
albumen. 
IV. Horns of Black Cattle. 
Under this name I reckon the horny sheaths which artists employ 
in the manufacture of a variety of articles which may be considered’ 
as indispensable necessaries of life, as combs, knife-handles, watch- 
men’s horns, boxes, sheaths, &c. They must not be confounded 
with the bony horns, as those of the hart, &c. which are easily 
renewed when the animal drops them, and which are composed of 
quite different materials, These last contain generally much gela- 
' tine and earth of bones. The horny sheaths remain attached to 
animals during the whole of their lives, Sometimes, indeed, they 
lose them in consequence of disease. Of this the horn of a cow, 
with which I made my first experiments, furnishes us with an 
example. The composition of these bodies is quite different from 
that of true horns, and perhaps it deserves attention that, besides 
the uncombined acid which I discovered in the epidermis, they 
contain likewise a peculiar liquid oil. Their composition indicates 
clearly that they must be considered as indurations anid extensions 
of the epidermis. 
(a) From 4 to 6 oz. of horn shavings were mixed with 12 oz. of 
water, and distilled. The distillation was stopped when 5 oz. of 
the water had come over. The liquid which had come over was 
mifky, and had a very strong smell of horn, while what remained 
in the retort was free from smell. Eveu after an interval of some 
days I could observe no drops of oil floating on the water, but the 
matter which occasioned the smell of horn had subsided, under the 
form of a greyish-white cloud. After 8 or 14 days some flocks 
subsided, but the cloud remained unaltered. 
This holds both with the horns of cows and oxen. 
(b) Fifty grains of the fine shavings of a cow’s horn were boiled 
for an hour in at least 12 oz. of water, and the water was renewed 
in proportion as it evaporated. By this means it was deprived of 
four grains of its weight. The concentrated solution did not in the 
least gelatinize. It reddened litmus paper, and had a very shar 
salt taste. Alcohol, and the solutions of barytes, acetate of teak, 
