C H EM I 
fbe femen at every temperature, when once this fluid has 
become liquid. This, Vauquelin obferve's, (hows that 
fome change takes place, either in the texture, or or¬ 
ganization, or intimate nature, of the femen, during its 
liquefaction. 
9. All the acids, excepting the. oxygenated muriatic 
acid, difl'olve the feminal.liq.uor very readily. Alkalis 
cannot difengage it afterwards under a folid form. The 
oxygenated muriatic acid, inftead of diffolving it, re¬ 
duces it into white flakes, which become yellow, if a large 
quantity of this acid be added. Urine, by means of 1 its 
difengaged acid, likewife dillfolves the feminal matter. 
10. The feminal liquor when frefh, does not decom- 
pofe barytic falts; but it decompofes them after being 
long expofed to the air. This effed is owing to the car¬ 
bonic acid of the air, which is abforbed by the foda con¬ 
tained in the femen, and which communicates to it the 
property of decompofing barytic falts. All the calcare- . 
ous, magnefian, and aluminous, falts, are decompofed by 
the femen, becaufe the foda has a ftronger attraction for 
acids than thefe earthy matters have. The metallic falts 
are itill more readily decompofed by this fubftance. 
11. By diftillation, the dry femen affords, 1. Some drops 
of water; 2. An elaftic fluid, confifting of carbonic acid, 
and of carbonated hydrogen gas; 3. An empyreumatic 
oil; 4. Carbonatof ammoniac ; 5. A very light charcoal 
remained in the retort. 
12. To difcoverthe proportions of the fubftances which 
the preceding experiments had difcovered in the femen, 
Vauquelin took forty grains of it in a dry ftate, which 
was equal to 400 grains of it when frefh, fince it lofes 
nine-tenths of its weight by drying, and heated them in 
a crucible of very pure white clay. This fubftance fwell- 
ed, emitted yellowifh ammoniacal fumes, and was con¬ 
verted into charcoal, when a very ftrong heat difengaged 
no longer any from it; the crucible was taken from the 
fire, the charcoal which it contained waswafhed, and the 
lixivium afforded, by evaporation, eight grains of a fait, 
known by its properties to be carbonat of foda. The 
lixiviated charcoal was again expofed to the fire,it burned 
readily, and twelve grains of white allies remained, which 
had no bafte, which did not difl'olve in water, and which 
melted with the blow-pipe into an opaque globule, that 
emitted a phofphoric light, while it continued in fufion. 
This fubftance difl'olved in acids, its folution was preci¬ 
pitated in white flakes by all the alkalis, and by lime-wa¬ 
ter. A folution of it in muriatic acid evaporated to dry- 
nefs, and afterwards treated with highly redified alcohol, 
was divided into two portions ; one of thefe, difl'olved 
in alcohol, afforded, with the oxalic and fulphuric 
acids, precipitates of the oxalat and fulphat of lime, and 
with potafh of pure lime. The other portion, which re¬ 
mained of a thick confiftence, was melted by the blow¬ 
pipe into a tranf'parent glafs, which was l'olubk in water, 
and the folution of which precipitated lime-water, and 
reddened blue vegetable colours. This analyfls proves, 
that this laft fubftance is compofed of lime, and of phof¬ 
phoric acid, like the bafis of bones. It follows, from 
the preceding experiments, that the human femen is com-- 
pofed, 
1. Of animal mucilage, - 6 parts. 
2. Of foda, - - 1 
3. Of phofphat of lime, - 3 
4. Of water, - -' - 90 
100 
The food, by which animals are fupported, contains a 
large quantity of matter, which is not capable of nou- 
jifhing them, and is rejected out of the.inteftines in a fo¬ 
lid form. The excrements are coloured by a portion of 
bile, which they carry with them. The fetid odour they 
exhale, arifes from the commencement of putrefadion in 
their paflage through the inteftines, Homberg is the 
Von. IV. No. 203. c 
S T R Y. 369? 
only chemifli who has examined thefe matters. He ob- 
ferved, that the phlegm afforded by excrements diftilled 
on the water-bath, was of a naufeous fmell; by walking 
and evaporation, he obtained a fait, which melted like 
nitre, and took fire in dole vefl’els. The diftillation of 
this matter, in a retort, afforded the fame products as 
other animal fubftances. Putrefied excrements afforded 
an oil without colour or linell, which did not convert 
mercury into filver, as he had been led to expedt. It 
mult be obferved, that the fecal matter examined by 
Homberg, was thatof men,fed with coarfe bread and cham¬ 
paign wine ; a circumftance which was laid to be eflen- 
tial, in order to fucceed in the alchemical experiments 
he was diredled to make. There can be no doubt, but 
that the properties of the excrements mult depend on the 
nature of the food, of which they are merely the relidue. 
An accurate and careful analyfis- of the excrements of 
different claffes of animals, is one of the moft certain 
means of difcovering the phenomena of digeltion. Se¬ 
veral cliemifts are at prefent engaged in it. 
Of the SOLIDS of ANIMALS.- 
The organs of carnivorous animals are divided into- 
three dalles. The firlt comprehends the white or loft 
parts, as the Ikln, the tendons, the membranes, the in¬ 
teguments, the aponeurofes, the ligaments, &c. The fecond 
includes the mufcular organs, which are red in fome ani¬ 
mals, white or grey in others. The third confilts of the 
hard parts, as the hair, the nails, the fcales, or lhells, the 
cartilages, the bones, &c. 
Of the soft and white- Parts. 
The firff white organ is the Ikin, a very elaftic body* 
fufceptible of changing its dimenfions, and fwelling up 
in water; which is common to all the white parts, but 
not to the mufcles. They are all capable of abforbing 
water with tannin and alum; expofed to the air, they 
dry up, forming glue, jelly, &c. When (kin has been 
tanned, it is no longer foluble in water; it is then a com¬ 
bination of gelatin and tannin. It becomes brittle and 
unchangeable; Fourcroy regards it in this ftate as an an- 
tifeptic, more powerful than bark in external dilorders. 
The texture of the dermis is not of the fame nature as 
that of the epidermis, which eafily peels off in tranfparent 
lamina, while the dermis, lying underneath, is more 
folid and fixed; it contains fibrin and albumen, which 
keep it compad even in a ftate of ebullition. Chaptal 
has made fome recent experiments on the epidermis. He 
found that the epidermis of. the human lkin was perhaps 
the moft diftind, and the molt eafily detached. The hu¬ 
man lkin becomes tough, like horn, by the heat of water, 
and furnifhes two diltind parts, epidermis and leather, 
which laft in its confiftence refembles foftened cartilage 3 
but the continued adion of hot water diffolves the lea¬ 
ther, without affedirig the epidermis. Neither will hot 
alcohol, long kept in digeltion over epidermis, attack it 
in the lealt. Cauftic alkali diffolves it; lime produces the 
fame effed, though more (lowly. Hence we perceive 
analogy between the exterior covering- of the human 
body, and the covering or outer part of filk. 
From thele principles Chaptal has drawn confequences 
which may be ufeful in tanning. 1. If a (kin covered 
with its epidermis be plunged into an infufion of tan, the 
tan will ad only on the inner or flelhyfide, the outer fide 
being guarded by the epidermis, which is incapable of 
• any combination with the tan. 2. When, by the adion 
of the cleanfing matter, the epidermis is taken away, the 
tan penetrates both fidesof the lkin. 3. The lime gene¬ 
rally ufed for this purpofe feems to ad only by diffolving 
the epidermis; lime-water has more adion than quick¬ 
lime ; but its effed ceales the moment the fmall portion 
of lime which was held in folution becomes combined; 
hence the neceflity of renewing the lime-water to finilh 
the cleanfing. 
Of 
