478 
from the same parts in a recent, or even 
in a fossile state, unless they had under- 
gone’such achange. - 
M. Vauquelir has also been enaase'l 
during the present year, in conductin g 
series of accurate and interesting ete. 
ments on- hai. By dissviving it in wa- 
ter by means of Papin’s digester, and af 
terwards examining the solution and its 
residuum, he succeeded in extracting 
mine difierent Substances; an animal 
matter similar to mucilave, two kinds of 
oil, iron in a peculiar state; some partie 
eles of oxyde. of manganese, phosphate 
and a small portion of carbonate of 
_ lime, a considerable portion of silica, and 
much sulphur. Black hair yielded an 
oil of the same colour, while red hair 
wrodueeda reddish-coloured oil, and 
white ‘oné- wholly colourless. ‘The last 
eotitained: always am excess of sulphur, 
and the white, m particular, magnesian 
plosphate. : 
Besides these theoretical researches, 
chemical principles have been applied to 
many useful practical purposes; among 
which M. Cuvier mentions a-mode of 
intating Roman alum, discovered  to- 
wards the conclusion of the former year, 
and which has succeeded so completely 
that the alum manafactured in this man- 
ner is sold at the same price as the genu- 
me Roman alum. This method merely 
consists in calciming and. re-crystalliz- 
inz the common alum, in order to de- 
prive it of its swper-abundant acid. M, 
Curaudeau contends, however, that it is 
also. necessary to oxygenize the small 
portion of irom usually contained in alum, 
to its marimum. But a memoir lately 
published by Messrs. Thenard and Board 
has perfectly cleared up this subject; 
from this we learn that a thousandth part 
of iron will sensibly influence the effects 
ef alum as amordant; and it is to deprive 
it even ‘of this small quantity to which 
the efforts of our manufacturers ought 
chiefly to-be directed. 
The oxygenation of the iron appears 
extremely well calculated to answer this 
intention, since it renders it inscluble in 
the acid. 
‘Fhe application of the oxygenated 
muriatic acid gas to the dgstiuction or cor- 
rection of conlagious miasmata, has, we 
are informed by M. Cuvier, been much 
extended during the present year, and 
its beneficial effects confir med by sete ye 
extensive trials. M. Desgennettes has, 
in particular, constantly. employed it in 
the Military: Llospital of Val-de-Grace ; 
and he has transmitted to the Institute 
Proceedings of Learned Societies. 
[June 1. 
a comparative view of the cases in whicly 
these fumigations not only prevented the 
communication af the disease, but ap- 
peared to assist in their cure when Ac- 
tually produced, . oT 
M. Pinel’ has-ex :perienced similar suc= 
cess by . ae employment of the same 
means in Hospital of & Salpetritre; 
and the peneelat effects resulting from 
its use in Madrid, as well asin “other 
gee in Spam, have already been made 
snown to the public thre ¢ med 
of different Spanish Jonna ic an 
We next learn from M. Cuvier’ s report: 
ments onthe fossile grinders of elephants 
to examine others in a recent state 3. and 
an occasion having presented itself in the 
‘course of a few years of dissecting. two 
elephants, nearly full grown, he,was by _. 
that means enabled to Ghscree. with greaty | é 
er precision the growth of the teeth ir 
these animals, and thence te-deduce con~ 
clusions respecting dentition in general. i 
The anatomy of large animals, he ob-= 
serves, may. justly be considered as a 
kind of natural microscope, which .as- 
sists in dscovering that of the smaller 
kind. It was Cah a view to confirm the 
doctrine of the late Jcehn Hunter, that 
M. Cuvier was induced to enter-into this 
investigation, at least so far as regards 
“the osscous povtion of the teeth. Tei is 
not furnished. with vessels, nor formed 
by Intus-susception, like true bones, but 
by a successive transudation of layers 
produced by the pulp of the teeth, and 
which lie over each othér. The enamel 
is deposited above by the membrane 
which envelops the young tooth, and is 
attached to it by’a species of crystalliza~ 
tion; in fine, a third substance, peculiar 
to some lerbivorous animals, is depo- 
sited after the enamel, but by the same. 
membrane, which changes its nature at 
a certain period. 
This third substance was first disco- 
-vered by M. Tenon, who_has termed it. 
the osseous corter, but who conceives it to 
be formed by the ossification of the cap- 
sular membrane. This intelligent anato- 
mist, M. Cuvier informs us) has commu- 
nicated-to the Institute, during the pre- 
sent year, the results of some well-de- 
vised experiments ou the teeth of the 
cachalot, and on those of the crocodile, 
from which it appears that the first have 
no enamel, but onjy an osseous cortex. 
They are easily dis tinguished from each | 
other, because the "enamel is much 
harder, and dissolves entirely in acids, 
without leaving any gelatinous parenchy- 
& Nias. 
swediuan., ; 
i 
that he himself was led by his experi~ 
way 
: oe SY: 
rae 
