CONCRETION FROM A HORSE 5 S STOMACH. 
ART. XX.— ANALYSIS OF A CONCRETION FROM A HORSE'S 
STOMACH. 
By Charles M. Wetherill and M. H. Boye, M. D. 
{From the Proceedings of the American Phil. Society , March, 1846.) 
This concretion, for a fuller description of which in con- 
nection with its history Dr. B. referred to his friend, Dr. B. 
H. Coates, by whom it was handed to him for examination, 
is remarkable for its size, weighing 111 lbs. 
It is of an oval shape, smooth surface, brownish-grey 
colour, and breaks in concentric layers of different thick- 
nesses, exhibiting a fibrous or radiated structure. The outer 
layer alone was analysed. The concretion was found by 
Dr. Coates to contain a nail in its centre. 
By a qualitative examination it was found to consist of 
phosphoric acid, magnesia, ammonia, chemically combined 
water, a small portion of organic matter and silex. It con- 
tained no lime. In order to determine quantitatively these 
ingredients, a portion was dissolved in dilute chlorohydric 
acid — the insoluble residue collected on a counterpoised 
filter, dried, and weighed ; after incineration and weighing, 
it yielded insoluble inorganic matter 0.45 per cent, which, 
deducted from its former weight, gave insoluble organic 
matter 0.64 per cent. To the filtered solution, was added 
a weighed portion of iron wire, dissolved in nitro-muriatie 
acid, and the whole then precipitated by ammonia. Hav- 
ing previously ascertained the amount of peroxide of iron, 
yielded by an equal portion of the same iron wire, the dif- 
ference in weight of these two precipitates gave for the 
Phosphoric acid 32 .40 per tent. 
To the filtered solution from the phosphoric acid, was 
added caustic potash in excess, and the whole boiled until 
the ammoniacal vapours were effectually expelled, and the 
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