as first demonstrated by Sfeguin, who disco- 
h'ed the above method of detecting them, 
'heir quantity in healthy urine is very small, 
ruikshank found that the precipitate afiord- 
d by tan in healthy urine amounted to — ^o-th 
art ol the weight ot the urine. It is to these 
Libstances 'that the appearance of the cloud, 
s it is called, or the mucilaginous matter, 
[hich is sometimes deposited as the urine 
bols, is owing. It is probable that healthy 
rine contains only gelatine, and not albumen, 
hough the quantity is too small to admit of 
bcurate examination; but in many diseases 
he quantity ot these matters is very much in- 
leased. The urine of dropsical people often 
ontains so much albumen, tiiat it coagulates 
ot only on the addition of acids, but even on 
le application of heat. In all cases of im- 
aired digestion, the albuminous and gelati- 
ons part of urine is much increased. This 
mns one ol the most conspicuous and im- 
ortant distinctions between the urine of those 
To enjoy good and bad health. 
' If urine is evaporated by a slow fire to the 
insistence of a thick syrup, it assumes a deep 
rown colour, and exhales a fetid aunnoniacal 
dour. \V lien allowed to cool, it concretes 
ito a mass of crystals, composed of all the 
omponent parts ot urine, it four times its 
might ot alcohol is poured upon this mass at 
ltervals, and a slight heat appl ied, the greatest 
art ot it is dissolved. 1 lie alcohol, which 
as acquired a brown colour, is to be de- 
noted off, and distilled in a retort in asand- 
eat, till tiie mixture lias boiled for some time, 
nd acquired the consistence of a syrup. By 
lis time the whole of the alcohol has passed 
tl ; and the matter, on cooling, crystallizes in 
qadrangular plates which intersect each other. 
. his substance is urea, which composes 
f the urine, provided the Watery part is ex- 
haled. To this substance the taste and 
nell bf urine are owing. It is a substance 
hich characterizes urine, and constitutes it 
Tat i t is, and to which the greater part of the 
ery singular phenomena of urine is to be as- 
libed. (See Urea.) 
It may be detected by evaporating urine to 
he consistence of a syrup, and pouring into 
\ concentrated nitric acid. Immediately a 
reat number of white shining crystals appear 
a the form of plates very much resembling 
rvstallized boracic acid. These chrystals are 
jrea combined with nitric acid. 
The quantity of urea varies exceedingly in 
liferent urines. In the urine voided soon 
fter a meal, very little of it is to be found, 
nd scarcely any at all in that which hysterical 
atients void during a paroxysm. 
According to Fourcroy and Vauquelin, the 
olour of urine depends upon the urea: the 
reater the proportion of urea, the deeper the 
olour. But Proust has detected a resinous 
latter. in urine similar to the resin of bile; 
nd to this substance he ascribes the colour 
I urine. If urine, evaporated to theconsist- 
nce of an extract, is mixed with sulphuric 
cid and distilled, this resin, he informs us, I 
Iparates during the distillation. What is '' 
rst obtained is soft, but the’last portions are 
1 the state of a dry powder. The consist- 
nce and colour of this resin resemble castor: 
|is very soluble in alcohol, and precipitated , 
tom its solution by water: but it is also so- 
lble in water ; and, according to Proust, is k 
trniNE. 
the resin of bile, somewhat modified by its 
passage through the urinary organs. 
It urine is siowly evaporated to the consist- 
ence of a syrup, a number of crystals make 
Ineir appearance on its surface : these possess 
the properties of muriat of soda. Urine 
therefore contains muriat of soda. It is well 
known that muriat of sooa crystallizes in cubes ; 
but when obtained from urine it lias the form of 
octahedrons. 1 his singular modification of 
its form is owing to the action of urea. It has 
been long known that urine saturated with 
muriat of soda deposits that salt in regular 
octahedrons. 
The saline residuum which remains after 
the separation of urea from crystallized urine 
by means ot aicohol has been long known 
under the names of fusible salt of urine and 
microcosmic salt. Various methods of ob- 
taining it have been given by chemists ; from 
Boerhaave, who first published a process, to 
Rouelle and Chaulnes, who gave the me- 
thod just mentioned. Jf the saline mass is 
dissolved in a sufficient quantity of hot water, 
and allowed to crystallize spontaneously in a 
close vessel, two sets of crystals are gradually 
deposited. The lowermost set has the figure 
ot fiat rhomboidal prisms ; the uppermost, on 
the .contrary, has the form of rectangular ta- 
bles. 1 hese two may be easily separated bv 
exposing them for some time to a dry atmo- 
sphere. The rectangular tables effloresce and 
fall to powder, but the rhomboidal prisms re- 
main unaltered. 
\\ hen these salts are examined, they are 
found to have the properties of phosphats. 
The rhomboidal prisms consist of phosphat 
ol ammonia united to a little phosphat of 
soda; the rectangular tables, on the contrary, 
are phosphat of soda united to a small quantity 
of phosphat of ammonia. Urine, then, con- 
tains phosphat of soda and phosphat of am- 
monia. 
When urine is cautiously evaporated, a few 
cubic crystals are often deposited among ihe 
other salts ; these crystals have the properties of 
muriat of ammonia. Now the usual form of the 
crystals of muriat of ammonia is the octahe- 
dron. I he change of its form in urine is pro- 
duced also by urea. This salt is obtained in 
greater abundance when the crystals of urea 
obtained from the alcohol solution are dis- 
tilled. 
When urine is boiled in a silver bason it 
blackens the bason ; and if the quantity of 
untie is large, small crusts of sulphuret of sil- 
ver may be detached. Hence we see that 
urine contains sulphur. This sulphur exhales 
along with the carbonic acid when the urine 
putrefies; for the fumes which separate from 
urine in that state blacken paper stained with 
acetat of lead. 
Urine, then, contains the following sub- 
stances : 
1 . Water, 
2 . Phosphoric acid, 
3. Phosphat of lime, 
4- Phosphat of magnesia, 
5. Carbonic acid, 
6. Carbon at of lime, 
7. Uric acid, 
8. Rosacic acid, 
9. Benzoic acid, 
10 . Gelatine and albumen, 
11. Urea, 
87i 
15. Resin, 
13. Muriat of soda, 
14. Phosphat of soda, 
13. Phosphat of ammonia, 
10. Muriat of ammonia, 
17. Sulphur. 
I ucse aie the only substances which ar<j 
constantly found in healthy m ine ; but it con- 
tains also occasionally other substances. Very 
o ten muirat ot potass may be distinguished 
among the* crystals which form during its t*va- 
poration. 1 ire presence ol this salt may al- 
ways be detected by dropping cautiously some 
tartaric acid into urine. It it contains muriat 
of potass, there will precipitate a little tartar, 
which may easily be recognized bv its pro- 
perties. 
Urine sometimes also contains sulphat of 
soda, and even sulphat of lime. The pre- 
sence of these salts may be ascertained by 
pouring into urine a solution of muriat of ba- 
rytes ; a copious white precipitate appears, 
consisting ot the barytes combined with phos- 
phoric acid, and with sulphuric acid if any is 
present. This precipitate must be treated 
with a sufficient quantity of muriatic acid. 
The phosphat of barytes is dissolved, but th« 
sulphat ot barytes remains unaltered, 
No substance putrefies sooner, or exhales 
a more detestable odour during its spontane- 
ous decomposition, than urine ; but there is 
a very great difference in this respect in dif- 
ferent urines. In some, putrefaction takes 
place almost instantaneously as soon as it is 
voided ; in others, scarcely any change ap- 
peals ior a number of days. Fourcroy and 
Vauquelin have ascertained that this difference 
depends on the quantity of gelatine and albu- 
men which urine contains. \V hen there is very 
little of these substances present, urine re- 
mains long unchanged ; on the contrary, tiie 
gieaier the quantity ot gelatine or albumen, 
the sooner does putrefaction commence. The 
putrefaction of urine, therefore, is in some 
degree the test of the health of the person 
who has voided it: fora superabundance of 
gelatine in urine always indicates some defect 
in the power of digestion. 
The rapid putrefaction of urine, then, is 
owing to the action ot gelatine on urea. We 
have seen already the facility with which that 
singular substance is decomposed; and that 
the new products into which it is changed are, 
ammonia, carbonic acid, and acetic acid. Ac- 
cordingly, the putrefaction of urine is announ- 
ced by an ainmoniacal smell. Mucilaginous 
Hakes are deposited, consisting of part of the 
gelatinous matter. I he phosphoric acid is 
saturated with ammonia; and the phosphat of 
lime, in consequence, is precipitated. Am- 
monia combines with the phosphat of mag- 
nesia; and forms with it a triple salt, which 
crystallizes upon the sides of tiie vessel in the 
form ot white crystals, composed of six- 
sided prisms, terminated by six-sided py- 
ramids. r i he uric and benzoic acids are 
saturated with ammonia ; the acetic acid, ancl 
the carbonic at id, which are the products of 
the decomposition of the urea, are also satu- 
rated with ammonia ; and notwithstanding the 
quantity which exhales, the production of 
this substance is so abundant, that there is a 
quantity of unsaturated alkali in the liquid. 
Putrefied urine, therefore,' contains chiefly the 
following substances, most of which are the 
prod u c ts ofp u Refaction: 
