ESSAY ON SECRETION. 
69 
fluid that normally should be separated from the blood by 
some other secreting organ ; and secondly, the power which 
we possess of artificially modifying these processes. 
The explanation of the first of these, which I think most 
consonant with all the facts of the case, is this; that if two 
glands separate from the blood similar or identical materials, 
then an accumulation of these materials in the blood, con¬ 
sequent upon the suppression of one secretion, will be followed 
by an increased activity of the other: but that if the material 
so accumulated in the blood be of a different character to that 
removed by the other glandular organ, then it possesses no 
power to separate it from that fluid, and it can only escape 
by other organs, in consequence of its solution in the water 
of the blood, when the watery part of any secretion may 
become charged herewith. In this way it is that the urine, 
which always separates a large quantity of water from the 
blood, becomes charged with biliary matter, when the function 
of the liver is suspended. 
In reference to the second, I would observe that we can 
modify any secretion by the administration of a substance 
which, when in the blood, is separated therefrom by the gland 
forming the secretion ; and if the material which we have 
thus added to the blood be in great quantity, or possess any 
irritating properties, a large volume of blood will be caused 
to pass through the vessels of the gland, and thus the quantity 
of the secretion will be temporarily increased. 
There are one or two passages in Simon’s 6 Lectures on 
Pathology,’ which seem to me to place this subject in a very 
clear light. You will find them at page 234 et seq. 
Mercury, when exhibited as a medicine, is said to possess 
the power of increasing all the secretions by exerting such an 
influence on the blood as to cause the formation of those 
materials of which thev are constituted, and that in more than 
their usual quantity. It is also an increaser of the secretion 
of bile, passing out of the system in great part through the 
liver. 
The compounds of Antimony also are said to increase con¬ 
siderably the formation of urea by virtue of their action upon 
the blood. 
But with these two exceptions it appears to me that the 
only power of modifying the secreting processes with which 
we are yet acquainted, consists in the production of a greater 
vascularity than is natural, and consequently an increase at 
first in all the constituents of the secretion; but, after a short 
time, simply an increase of its watery parts; whichdepends upon 
