tween the animal and vital functions, as well as to resist the occasional impressions made on the body, by sudden vicissitudes of heat and cold, moist and dry air, &c.
All the arteries derive their origin from the ventricles of the heart; namely, the pulmonary artery from the right, and the aorta from the left; of which two the rest are branches. They terminate in veins, exhaling vessels, or anastomose with one another, that is, unite by inosculation. It is asserted by physiologists, that the circulation of the blood, its heat, red colour, fluidity, assimilation of food, &c. the conversion of fixed into volatile salts, and the performance of the different secretions, such as bile, urine, saliva, &c. all must be attributed to the contractile power of the arteries and the heart.—See Assimulation, Bile, Blood, Chyle, Saliva, Urine, &c.
It is farther worthy of notice, that an injury received by a very considerable vein, is not nearly so dangerous as that of a small artery, especially in the vicinity of the heart.—(See Bleeding, or Hemorrhage); and that single arteries times become ossified, or acquire a cartilaginous and bony consistence. In the larger ones, this phenomenon rarely occurs: yet a very remarkable instance of an ossification of the aorta is recorded by the celebrated Dr. Zimmerman, the author of the classical treatises "On Solitude," and "On National Pride," in his excellent work "On Experience in Physic;" which deserves to be read and studied by every medical and philosophical inquirer. Such preternatural production of bone is attributed to an abundance of earthy particles, which are, perhaps, generated by a too liberal use of tart wines, veal, potatoes, cheese, and all food that is hard and difficult of digestion. Fortunately, however, this fatal conversion of membraneous substance takes place only at an advanced age; but then it affords little or no hope of prolonging the parent's life.—See Heart, Pulse, Veins.
Arthritis. See Gout.
ARTICHOKE, or the Cynara, L. though an exotic, is a plant well known and much cultivated in this country. There are four species, but only two are reared for use, viz. the scolymus, or garden ardchoke, and the cardunculus, or cardoon, both of which are propagated by slips, or suckers, arising in spring, from the roots of the old plants. The slips should be taken from good plants in March, or the beginning of April, and set in an open quarter of the kitchen-garden, in rows at the distance of five feet from each other. By this process, artichokes may be produced in the autumn of the same year. The size of their fruit will gradually diminish, after the third or fourth year, though the roots continue sound for several seasons. The cardoon, which is a hardy plant, may be propagated by seeds sown in March. As these plants are very large, they ought to be placed at the distance of several feet from each other; and thus crops of spinach, endive, cabbage, or brocoli, may be raised between the rows. About Michaelmas, the cardoons generally attain to a considerable size; the leaves of each plant should then be tied, that they may be hoed, for the purpose of blanching; which
