606 ON THE LACTEAL AND 
fore as well have carried this action to the inouths of these ves¬ 
sels. 
As we know nothing of the mode of the action of the mouths of 
these vessels, it is impossible we can form any opinion that can 
be relied upon; but as they are capable of absorbing substances 
in two different states, that of solidity and fluidity, it is reasona¬ 
ble to suppose that they have different modes of action; for, al¬ 
though any construction of parts that is capable of absorbing a 
solid may also be such as is capable of absorbing a fluid, yet I 
can suppose a construction only capable of absorbing a fluid, 
and not at all fitted for absorbing; a solid, though this is not like- 
ly; and, to see the propriety of this remark more forcibly, let us 
only consider the mouths of different animals, and I will venture 
to say, that the mouths of all the different animals have not a 
greater variety of snbstances to work upon than the absorbents 
have : and we may observe, that, with all the variety of mouths 
in different animals, this variety is only for the purpose of adapt¬ 
ing them to absorb solids, which admit of greater variety in 
form, texture, &c. every one being capable of absorbing fluid 
matter, which admits of no variety*.” 
Mr. J. Hunter, after attributing such a wonderful power to the 
mouths of these absorbent vessels, and almost leading us to be¬ 
lieve that they possessed a power of breaking clown and acting 
on the more solid parts of the living body, in a similar manner to 
the months and teeih of animals , in the next place treats of 
“ ulcerative absorption, insterstitial absorption, progressive ab¬ 
sorption, modelling absorption, and of the remote cause of the ab¬ 
sorption of the animal itself all of which I shall notice in their 
proper place, as also the manner in which I consider absorption 
to take place. 
The immediate followers of Mr. J. Hunter have also gone so 
far as to insist on teaching us, that in infancy and youth the ar¬ 
teries act as equal to two, while the absorbents act as equal only 
to one. On the contrary, in old age , or the latter periods of life, 
the scale then becomes turned with these absorbents , for they act 
as equal to two , while the arterial system then acts as equal to 
only one. 
These notions may appear very plausible to those who only 
take a superficial view of the subject of absorption; but let me 
ask, if in infancy and youth the arteries act as equal to two , and 
the absorbents as equal only to one, where are those arteries which 
are considered as not to be capable of absorbing,—where, I ask, 
are they to obtain the materials by which they are gradually en- 
* Hunter on the J31oo<J, ike. Vol. ii, p. 285, 286. 
