EMILY.
There seems to be a singular analogy between the blood of animals and the sap of vegetables; for each of these fluids contains the several materials destined for the nutrition of the numerous class of bodies to which they respectively belong.
MRS. B.
Nor is the production of these fluids in the animal and vegetable systems entirely different; for the absorbent vessels, which pump up the chyle from the stomach and intestines, may be compared to the absorbents of the roots of plants, which suck up the nourishment from the soil. And the analogy between the sap and the blood may be still further traced, if we follow the latter in the course of its circulation; for, in the living animal, we find every where organs which are possessed of a power to secrete from the blood and appropriate to themselves the ingredients requisite for their support.
CAROLINE.
But whence do these organs derive their respective powers?
MRS. B.
From a peculiar organisation, the secret of which no one has yet been able to unfold. But it must be ultimately by means of the vital principle that both their mechanical and chemical powers are brought into action.
I cannot dismiss the subject of circulation without mentioning perspiration, a secretion which is immediately connected with it, and acts a most important part in the animal economy.
CAROLINE.