| known under the name of jaundice. 
known by the popular designation of oat-hair 
calculi. Other kinds, usually found in voraciously 
feeding horses, are coarse agglutinations of the 
same matters which compose the preceding, and 
of pieces of stone, coal, and gravel, and of many 
sorts of coarse and indigestible ingredients, and 
are sometimes popularly known under the vile 
yet not altogether inappropriate designation of 
dung-balls. No medicinal appliance for expelling 
or reducing the intestinal calculi of horses has 
yet been discovered ; so that prevention, and not 
cure, must be studied. 
Biliary calculi occur in the gall-bladder of man 
and of some of the inferior animals. They exist 
sometimes solitarily, sometimes in groups of from 
three to six, and occasionally in almost incredible 
numbers. So long as they continue in the gall- 
bladder, they occasion little inconvenience ; but 
when they pass from that organ into the duct of 
communication with the duodenum, they gener- 
ally occasion much pain and squalor, and some- 
times almost totally obstruct the flow of the bile, 
and originate the disease which is popularly 
If they 
continue to obstruct the duct, death must event- 
| ually be the result ; but when they pass into the 
duodenum, either spontaneously, or under the 
influence of such medicinal appliances as aperi- 
ents, emetics, anodynes, and fomentations, they 
cease to cause injury, and allow the health to be 
immediately restored. The biliary calculi of man 
were supposed by Fourcroy and Thenard, to con- 
sist principally of a peculiar fatty matter which 
resembles spermaceti, and has been called adipo- 
cire ; but have been found by Chevreul, Turner, 
and other chemists, to consist, in general, of the 
yellow colouring matter of the bile and choles- 
terine, the latter predominating, and being some- 
times in an uncombined or pure condition. Yet 
some contain a large proportion of mere inspis- 
sated bile; and a few, though but a few, are 
wholly destitute of cholesterine. The biliary cal- 
culi of oxen consist almost entirely of that yellow 
colouring matter of the bile, which, from the 
beauty and permanence of its tint, is in high re- 
quest among painters. “ This substance,” re- 
marks Turner, “is readily distinguished by its 
yellow or brown colour, by insolubility in water 
and alcohol, and by being readily dissolved by a 
solution of potash. The solution has at first a 
yellowish-brown colour, which gradually acquires 
a green tint, and is precipitated in green flocks 
by muriatic acid. According to the observations 
of Tiedemann and Gmelin, the colouring matter 
is influenced by the presence of oxygen gas. The 
yellowish precipitate, occasioned by adding mu- 
riatic acid to bile, absorbs oxygen by exposure 
to the air, and its colour changes to green. The 
action of nitricacid is still more remarkable. By 
successive additions of this acid, the tint of the 
colouring matter may be converted into green, 
blue, violet, and red, in the course of a few se- 
_conds.” 
eee = 
CALCULUS. 
Urinary calculi occur in the kidneys, the ure- 
ters, the bladder, and the urethra of man and of 
almost all the domesticated animals. The urine 
of a healthy man is a combination of no fewer | 
than twelve or thirteen different proximate ele- | 
ments; the urine of man, under the action of 
several kinds of disease, includes some additional 
and very distinctive elements ; and the urine of | 
the greater number of the domesticated animals 
is, on the whole, as remarkable as that of man 
for complexity. Some of the proximate elements, 
as soda and ammonia, are alkalies ; some, as lime 
and magnesia, are metallic oxides ; and some, as 
hippuric acid in the horse, and uric, phosphoric, 
and oxalic acids in man and other animals, pos- 
sess the power of chemically attacking and neu- 
tralizing both the alkalies and the metallic ox- 
ides. In various conditions of the urinary organs, 
or of the absorbent and vascular systems, several 
of the combining elements rush into mutual 
union, and form solid precipitates and crystalline 
deposits, which possess the character of calculi, 
and occasion the irritations, inflammations, and 
other symptoms of the well-known diseases called 
gravel and stone. 
A frequent kind of urinary calculus consists 
of uric acid. A calculus of this kind is hard, 
smooth, inodorous, of a brownish or fawn colour, 
commonly of an oval form, and composed of con- 
centric layers, which are formed round a central 
nucleus, and are distinguishable from one ano- 
ther by slight differences of colour, and some- 
times by laminee or dustings of some foreign sub- 
stance. A calculus of urate of ammonia is very 
closely similar to the calculus of uric acid, being 
distinguishable by some peculiarities of behaviour 
under the test of chemical reagents ; but it is of 
exceedingly rare occurrence. An urinary calcu- 
lus of bone earth or phosphate of lime has a pale 
brown colour, and a remarkably smooth polish ; 
and, if cut through the middle, is seen to be com- 
posed of concentric layers, very regularly formed, 
and so slightly adherent to one another as to ad- 
mit of very easy separation. Some bone-earth 
calculi exhibit ammoniaco-magnesian phosphate 
in minute sparkling crystals, either on their sur- 
face or between their laminz; and a few calculi, 
comprising bone-earth, possess a preponderance 
of the ammoniaco-magnesian phosphate over the 
phosphate of lime, and these are generally whiter 
and less compact than the ordinary bone-earth cal- 
culi. A particular kind of urinary calculus techni- 
cally known as “the fusible,” consists of a mixture 
of the phosphate of lime and the ammoniaco-mag- 
nesian phosphate ; it has usually a white colour, 
and a rugged or otherwise uneven fracture ; it 
easily breaks, pulverizes, or separates into layers, 
and, when crushed or taken asunder with the 
hand, leaves a white dust upon the fingers ; and 
it is of comparatively frequent occurrence, and 
often attains a comparatively large size. An 
urinary calculus of oxalate of lime is shaped 
somewhat like the fruit of the mulberry, and, 
iva | 
| 
| 
| 
| 
