is only when these solutions are diluted to a 
certain degree with water that they are ab- 
sorbed by animal tissues. A dry bladder re- 
mains more or less dry in saturated solutions of 
common salt, nitre, ferro-cyanuret of potassium, 
sulpho-cyanuret of potassium, sulphate of mag- 
nesia, chloride of potassium, and sulphate of 
soda. These solutions run off its surface in the 
same manner as water runs from a plate of glass 
besmeared with tallow. Fresh flesh, over which 
salt has been strewed, is found, after 24 hours, 
swimming in brine, although not a drop of water 
has been added. The water has been yielded by 
the muscular fibre itself, and having dissolved 
the salt in immediate contact with it, and there- 
by lost the power of penetrating animal sub- 
stances, it has on this account separated from 
the flesh. The water still retained by the flesh 
contains a proportionally small quantity of salt 
having that degree of dilution at which a saline 
fluid is capable of penetrating animal substances. 
This property of animal tissues is taken advan- 
tage of in domestic economy for the purpose of 
removing so much water from meat that a suffi- 
cient quantity is not left to enable it to enter 
into putrefaction. In respect of this physical 
property of animal tissues, alcohol resembles the 
inorganic salts. It is incapable of moistening, 
that is, of penetrating, animal tissues, and pos- 
sesses such an affinity for water as to. extract it 
from moist substances. 
“ When a solution of a salt, in a certain de- 
gree of dilution, is introduced into the stomach, 
it is absorbed ; but a concentrated saline solu- 
tion, in place of being itself absorbed, extracts 
water from the organ, and a violent thirst en- 
sues. Some interchange of water and salt takes 
place in the stomach; the coats of this viscus 
yield water to the solution, a part of which, hav- 
ing previously become sufficiently diluted, is, on 
the other hand, absorbed. But the greater part 
of the concentrated solution of salt remains un- 
absorbed, and is not removed by the urinary 
passages ; it consequently enters the intestines 
and intestinal canal, where it causes a dilution 
of the solid substances deposited there, and thus 
acts as a purgative. Each of the salts just men- 
tioned possesses this purgative action, which de- 
pends on a physical property shared by all of 
them ; but, besides this, they exercise a medi- 
cinal action, because every part of the organism 
with which they come in contact absorbs a cer- 
tain quantity of them. The composition of the 
salts has nothing to do with their purgative ac- 
tion ; it is quite a matter of indifference as far 
as the mere production of this action is con- 
cerned (not as to its intensity), whether the base 
be potash or soda, or in many cases lime and 
magnesia, and whether the acid be phosphoric, 
sulphuric, nitric, or hydrochloric. If we drink, 
fasting, a glass of common spring water every 
ten minutes, a strong diuretic action becomes 
apparent, the quantity of salts in the water being 
121 
much less than that in the blood. When the 
second glass is taken, a quantity of urine is eli- 
minated, the weight and volume of which corre- 
sponds nearly to that of the first glass ; and by 
drinking twenty successive glasses of water, 
nineteen evacuations of urine take place, the last 
of which is colourless, and scarcely differs in its 
amount of saline ingredients from the spring 
water itself. When the same experiment is made 
with a water containing exactly the amount of 
salts as in blood (? to 1 per cent. of common salt 
for example), a separation of urine is not effected, 
and it becomes almost impossible to drink more 
than three glasses of such water. A sensation of 
fulness in the stomach, of pressure and weight, 
seem to show that water containing an equal 
amount of saline ingredients as blood, requires a 
much longer time to be taken up by the blood- 
vessels. When the water taken contains a larger 
amount of salts than that existing in blood, a 
more or less active purgative action ensues. 
Hence, we see that three kinds of action take 
place, according to the quantities of salt existing 
in the water. 
“ Besides these salts, the action of which does 
not depend upon their power of entering into 
combination with the component parts of the 
organism, there is a large class of others which, 
when introduced into the living body, effect 
changes of a very different kind, and produce 
diseases or death, according to the nature of these 
changes, without effecting a visible lesion of any 
organs. These are the true inorganic poisons, 
the action of which depends upon their power of 
forming permanent compounds with the sub- 
stance of the membranes and muscular fibre. 
Salts of lead, iron, bismuth, copper, and mercury 
belong to this class. When solutions of these 
salts are treated with a sufficient quantity of al- 
bumen, milk, muscular fibre, and animal mem- 
branes, they enter into combination with those 
substances, and lose their own solubility; while 
the water in which they were dissolved loses all 
the salt which it contained. The salts of alka- 
line bases extract water from animal substances ; 
whilst the salts of the heavy metallic oxides are, 
on the contrary, extracted from the water, for 
they enter into combination with the animal 
matters. Now, when these substances are ad- 
ministered to an animal, they lose their solu- 
bility by entering into combination with the 
membranes, cellular tissue, and muscular fibre; 
but in very few cases can they reach the blood. 
According to all the experiments yet made on 
the subject, it appears, that after the lapse of 
the same time as is required for the appearance 
of alkaline salts in the urine, the metallic salts 
above mentioned cannot be detected in that 
fluid. In fact, during their passage through the 
organism, they come into contact with many 
substances by which they are retained. By de- 
grees, however, the constituents of the tissues 
with which they have combined are altered by 
