Magendie on Absorption. 297 
with which they are in contact. For instance, if a certain 
quantity of ink be introduced into the pleura of a 
dog, in an hour’s time the pleura, the pericardium, eae in- 
tercostal muscles, and the surface of the heart itself will be 
sensibly tinged with black. (1) 
It appears then to be established beyond all doubt, that 
all the blood vessels, whether arterial or venous, great 
or small, in dead bodies or in living ones, possess in their coats 
(parois) a physical property by which we may perfectly ex- 
plain, and to which we may reasonably refer all the princi- 
pal phenomena of absorption. To aflirm sa =. email 
is the sole cause which —* that effect w e goin 
beyond the limits assigned: by sound aise nt 
ent state of known facts, I am acquainted with none which 
tend to invalidate this explanation ; on the contrary, they all 
tend to confirm the exactness of it. ag 
For example, Lavoisier and Mr. Seguin have proved, by 
a series of interesting experiments, that the skin, while cov- 
ered by its epidermis, does not absorb water, nor any other 
substance. But the epidermis is of a different nature from the 
vascular membranes; it is a sort of varnish which does not 
imbibe, as every one may observe on his own body whi 
ba ‘as soon as the epidermis is | at food 
absorbs like all other parts of the body, because the 
the vessels are then immediately in contact with om sub- 
stances destined to be absorbed. Hence the necessity of 
placing beneath the epidermis the substances to be absorbed 
in inoculation and vaccination; hence, also, the necessity 
of long continued frictions ; and, often the employment of 
greasy substances, to | facilitate the absorption of certain 
nidermia * 
nn 44: weaees vw aNAN 2 £445 
likewise, ae peeicreita given to those parts of the | 
we fae men is hes forte apheaton of 
s in our organization. — “effect 
ee the soposion that absorption & « 
(1) This is observable with. still grater facility in smaller eaieuah, 
1as ne guinea pigs, mice, &c. &c. _ 
eo 
Wet. IIL....No. Dn 
