The mucus contained in saliva in expectorated fluids, and in that
from the oyster, were first examined ; but since nitrate of silver and
acetate of lead, which have been supposed to detect mucus, were
found to act principally on the salts contained in them, it became
necessary to employ other means for the removal of the salts; and
the voltaic apparatus was applied for the purpose of extracting the
alkalies at one pole, and the acids at the opposite. But there oc—
curred a phenomenon that was wholly unexpected; as a considerable
coagulation of albumen took place at the negative pole, which Mr.
Brande (at the suggestion of Mr. Davy) is inclined to ascribe to the
separation of alkali with which it was combined, and to which its
solubility was owing.
It is observed, in confirmation, that when an egg is boiled for some time in water, the liquid becomes alkaline to tests, and still deposits, by electrization, a small quantity of albumen, which the alkali re- tains in solution. '
The coagulation of albumen by acids is also ascribed to their su- perior afl-inity for the alkali.
For discovering the nature of the saline ingredients, the water in which some white of egg had been boiled and macerated, was elec- trified by a. powerful battery, through the medium of a cup of water on each side. After the process had continued for one hour, the fluids were examined; that on the negative side contained a quan- tity of soda nearly pure, and that on the positive side a small quan- tity of albumen, with a little muriatic acid, but not enough to satu- rate the alkali.
. The same means of analytic investigation being applied to other fluids, detected larger quantifies of albumen than were discoverable by heat alone; as in saliva, in the mucus from the oyster, the mucus from the trachea, in bile, in milk, and in the liquor of Amnios: and hence the author is led to doubt Whether mucus may not be a. com- pound of albumen, either with muriate of soda or with excess of soda.
The separation, by electric powers, of substances chemically united, suggests the possibility, that since the same power is known to exist in the torpedo and electrical eel, it might be the means by which secretion in all animals is effected.
Since in these fish the abundance of nerves connected with the electrical organs proves that this power resides in them, and since the arrangement of many nerves in animal bodies has evidently no connexion with sensation, it seems not improbable that these may answer the purpose of supplying and regulating the organs of secretion.
With a View to determine what changes could be produced in the blood similar to secretion, Mr. Brande applied the power of twenty-
