C H E M : 
litliiafis. Urine has been the fource of difcoVeries highly 
valuable to the-chemift,-and mull be of others itiU more 
valuable to the phyfician. Cdhfnbring it firft as a lixi¬ 
vium, defigned-to carry out of the body a large quantity 
of faline matters, which wouid injure the due exercile 
of its functions, we muft not forget that it is an evacua¬ 
tion, the proportion of the principles of which, varying 
according to the ftate of the-body, becont-s a kind of 
ftandard to lliew the modifications of the body, in health 
or ficknefs, by a leries of obfervations, which phylicians 
have already commenced under fortunate aufpices. We 
fhould confider it, too, as always containing the matter 
of.renal and vefical concretions, which teem to require 
for their formation only a little longer refidence in the 
refpeftive organs than nature intended, or the prefence 
of a nucleus, which attracts, in fome meafure, the.fuc- 
ceflive lithic ftrata. We muft alfo obferve the propor¬ 
tions of the different principles in the urine, particularly 
of the uncombined acids it contains, and the phofphat 
of lime which it carries along with it; for thefe, differ¬ 
ing remarkably in difeafes of the joints, the aponeurofes, 
and the bones, will, at fome future period, become, in 
the hands of fkilful observers, new means of difcovering 
. the nature of thefe complaints, afcertaining their pro¬ 
gress, and, perhaps, infuring their cure. 
Little can be added here of the other animal fluids, 
flich as the infenfible perfpiration, fiveat, the gaftric juice, 
faliva, tears, the mucus of the nofe, the cerumen, the 
leminal liquor, &c. becauie'none of thefe fluids have yet 
been much examined. Ail have unquestionably their 
peculiar compofition, and diifer in fome points, particu¬ 
larly in the proportion of their principles. Some of thefe 
humours, with which modern experiments have render¬ 
ed us a little better acquainted, exhibit the union of a 
peculiar mucilage with water, pure foda, phofphat of 
lime, and phofphat of foda : fuchare. the tears, the nafal 
mucus, and the fpermatic fluid. Qf thefe the firft and 
Second difplay likewife the property of infpiflating by the 
contact of the air and the abforption of oxygen, which 
probably conflitutcs the maturity, as it is called, of the 
humours in catarrh, whether it be confined to the nofe 
and fauces, or extend to the lungs. The feminal liquor 
has. offered us the Angular phenomenon of the crystalli¬ 
zation ot phofphat of lime, which was never before 
known. On conlidering the whole of the l'olid matters 
which compofe the various textures of the different or¬ 
gans of animals, the fubftances of which they are formed 
may be divided into three principal genera: the firft 
comprehends the albumen ; the fecond, the gelatin, or 
gelatinous matter; the third, the fibrin, or fibrous mat¬ 
ter : two of thefe have already been distinguished above, 
under the article on the blood, we (hall therefore now 
only give a concife Sketch of the constant phenomena, 
which may be confidered as the characters of each of 
thefe genera. 
Genus I. Albumen: Coagulable by heat, acid, ox- 
yds, and, in general, by oxygen in a concrete or nearly 
concrete State; foluble by alkalis; found more or lei's 
condenfed or oxygenated, and interwoven in the mem¬ 
branes, tendons, cartilages, and, in general, all the white 
parts of animals. 
Genus II. Gelatin : Participating the folidity of the 
firlt in molt of the white organs, but capable of being 
feparated from it, and eafily diffolved by boiling water, 
to which it gives the form of a jelly on cooling. As it 
constitutes the bafe, or principal. part, of all the white 
organs in general, thefe are more or lefs completely foluble 
in boiling water, and form tranfparent jellies by the re¬ 
frigeration of thefe Solutions. 
Genus III. Fibrin : Infoluble in water, at any tem¬ 
perature; foluble in acids; containing a large quantity 
of azot; condenfed, concrete, and organized, in mu feu- 
lar fleSh, which may be regarded as the proper receptacle 
of all the fibrin contained in the blood: accordingly, 
confidering the mufcles as the Secretory organs of the 
S TRY. 171 
fibrous matter of the blood, we.ought to inveftigate all 
its modifications, with refpeft to the quantity or pro¬ 
portion which fixes in thefe organs, and more particu¬ 
larly.with regard to their apparent exclusion of it under 
various circumstances of dileafe, old age, &c. 
Thefe three matters, albumen, gelatin, and fibrin, in 
a ftate of concretion, of combinations of tw > and two, or 
all three together, and ei'pecially in different proportions, 
form all the folids of animals, and are Sept-able from 
each other by a Ample and eafy analysis: th.y ai fo, par¬ 
ticularly the albumen, form many of the fluids of ani¬ 
mals ; only in thefe they contain lefs oxygen, more wa¬ 
ter, and are combined with acids, neutral Saits, &c. It 
muft be obferved, that in the fluids, the gelatin is as de¬ 
ficient as in the folids it is abundant, appearing to ac¬ 
quire its nature, of gelatin in palling from the fluids to 
the folids. Albumen difiolved in acids by art aflumes 
properties analogous to thofe of gelatin. The folid ani¬ 
mal matter, or bony fubftance, is of another order of 
compofition. A large quantity of an earthy l’alt, almaft 
wholly infoluble, phofphat of lime is amafled in the tex¬ 
ture or primitive parenchyma of the bones. This is the 
.whole myftery oS the ftrufture and compofition of this 
part of the animal frame ; and for this reafon bones yield 
jelly on being boiled in water, and a considerable quan¬ 
tity of oil and ammoniac on diftillation ; and when tho¬ 
roughly calcined, or burnt, they are nothing more than 
calcareous phofphat, mingled with fome fmall portion of 
carbona'c, muriat, and phofphat of foda. 
When any one of tlie preceding- animal matters, par¬ 
ticularly of the condenfed white fluids, or white organs-, 
is treated with nitric acid, there will be extricated a 
more or lei’s considerable quantity of azotic gas, and of 
pruflic acid gas, which appears to be nothing but a com¬ 
bination of azot, hydrogen, and carbon, with a little 
oxygen. Gelatin yields the leaft, albumen lomewhat 
more, and fibrin the 1110ft. In proportion as this change , 
of combinations in the principles of animal matters is 
effefted by means of the nitric acid, they feem to revert 
to their ancient ftate of vegetable matter, from which 
they do not effentially differ, as has already been laid, 
but by the prefence of azot, their proportion of carbon 
and hydrogen not being the fame, and greater compli¬ 
cation in the number of principles, from a combination 
of which they are formed. Thus, inftead of being ter¬ 
nary compounds, as vegetable fubftances are, animal 
matters are quaternary compounds, and even Hill more 
complicated. Azot is the fourth primitive principle, 
which is fu per added to hydrogen, carbon, and oxygen. 
Accordingly, the converlion of vegetable into animal 
matter, which confifts only in the fixation or addition of 
azot, muft-be confidered as the principal phenomenon of 
animalization : this alone explains its chief myfteries; 
and, when once we are perfeftly acquainted with the rae- 
ctianilin of this addition of azot, molt of the functions of 
the animal economy, which eft’eft it, or depend on it, will 
become equally known. 
What we already know of the fubjeft, is confined to 
the following confiderations : the phenomenon is not fo 
much owing to the fixation of a new quantity of azot, 
as to the fuktraftion of other principles, which increafe 
its proportion. In refpiration, the blood exhales a large 
quantity of hydrogen, and of carbon, either limply dif- 
folved in hydrogen gas, or converted into the ftate of 
carbonic acid by the very aft of circulation, and in the 
vafeuiar l'yftem, according to fome modern philofophers. 
In the cavities of the bronchia, during the aft .of refpira¬ 
tion, and by the ir.ftrumentality ot this aft, the hydro¬ 
gen forms water, which exhales in expiration. A por¬ 
tion of oxygen appears at the fame time to become fixed 
in the pulmonary blood, and, circulating with this fluid 
through the vefiels, gradually combines with the carbon, 
to as to form that carbonic acid, which is extricated from 
the venous blood in the lungs. It is ealy to conceive, 
that, by thus dilengaging a large quantity of hydrogen 
