280 
DR. MARCET ON THE IMMEDIATE PRINCIPLES OF 
The following are the peculiarities which the examination of those excrements 
presented : — 
Castings of the Horse. — Horse’s excrements, boiled with alcohol, yielded but a 
very scanty deposit on cooling ; but the solution, mixed with milk of lime, gave a 
yellow precipitate of a light homogeneous nature. The ethereal extract from this 
precipitate, evaporated spontaneously for twenty-four hours, left a yellow residue 
viewed under the microscope as drops of oil; but not a trace of excretine could be 
detected. The filtrate from the lime precipitate, concentrated on the water-bath, 
did not yield any butyrate of lime. 
Castings of the Sheep. — Newly-passed castings of the Sheep, washed with a little 
alcohol and boiled in that liquid, gave a deep green extract, in which milk of lime 
produced a very abundant green precipitate, the liquid remaining yellow. This pre- 
cipitate, collected on a filter and treated with ether, yielded a dirty dark green 
solution, which, allowed to evaporate spontaneously, deposited after twenty-four 
hours a green mass, observed under the microscope to consist of an amorphous and 
a crystalline substance. The latter, though not distinctly defined, possessed a yellow 
colour, refracted light very readily, and polarized. No substance resembling excre- 
tine was obtained. From the difficulty of separating the above crystalline substance 
from the green amorphous matter, the investigations on this part of the subject are 
necessarily imperfect. 
The filtrate from the lime precipitate did not yield any butyrate when con- 
centrated. 
Castings of a Dog fed upon bread. — The castings of a Dog fed for about a month 
upon nothing but bread gave a very pale alcoholic extract, yielding but a slight 
deposit on cooling. The precipitate produced by the addition of lime to this extract 
was of a yellow colour, and when treated with ether, prismatic crystals were obtained 
by its spontaneous evaporation, usually grouped three or four together, meeting at one 
extremity and diverging at the other. Some groups had a less defined character, 
and resembled leaves converging at one of their extremities ; they polarized light 
beautifully. These same crystals were obtained in one instance from the castings 
of a dog fed upon meat, of vvhich they are probably merely a modification. 
Castings of the Boar. — Faeces from the Wild Boar were procured fresh from the 
Zoological Gardens, the animal being fed upon biscuit and cabbages. These cast- 
ings occurred in the form of green masses, having an alkaline reaction. When 
washed with a little water and boiled in alcohol, they yielded a dark green solution. 
An abundant deposit occurred on cooling, from which the fluid was decanted. Milk 
of lime added to the solution produced a yellow precipitate, as in the previous cases. 
It was treated with ether, which was allowed to evaporate spontaneously. After a 
week a green deposit was obtained, composed of an amorphous green oil and arbo- 
rescent crystals, readily polarizing light ; they had not, however, the peculiar 
look of excretine, and did not crystallize in tufts like that substance. The filtrate 
