ACETO-ORTHO-TOLUIDE. — Aceto ortho-toluide is an isomer of exalgin, and appears in the form of colorless needles, freely soluble in alcohol, ether, and hot water, but little soluble in cold water. Its melting-point is 22-I.6° F. and boiling-point 564.S° F., being com parable in these respects to acetanilid and methylacetanilid, which it resembles chemically, being also, like these drugs, an active antipyretic.
Physiological Action. — Aceto-ortho tolnide acts chiefly on the cord, and only in toxic doses on the brain and medulla. The heart is last affected. Doses of V, grain per kilogramme of the body-weight reduce normal temperature by about 1 V,' F., and bring febrile temperatures to the normal point. It does not alter the blood-pressure, but somewhat increases the frequency of the heart-beats, though leaving the vasomotor centres unaffected. It causes dilatation of the blood-vessels by direct stimulation of the nervous ele ments of the vascular walls themselves. The fall of temperature is, moreover, due to the loss of heat consequent on this dilatation. (Barabini.) Therapeutics.—Although this product was introduced as one superior to ace tanilid, owing to its being less toxic, it does not seem to have received much support from the profession. It was also credited with antiseptic properties even in a weak solution (5 to 1000).
ACETYLENE.—When calcium carbide (CaC.) is brought in contact with water, acetylene-gas is formed. Being capable, when lighted, of furnishing a degree of light far superior to that of ordinary gas, acetylene has recently been considerably used as an illuminant. When prepared from pure calcium carbide and purified by liquefaction, it has a pleasant ethereal odor and can be breathed in small quan tities without giving rise to ill effects. Impure gas, prepared from coal or im pum lime, may contain calcium sulphide and phosphide, and the acetylene pre pared from it may then have a very unpleasant odor.
Acetylene Poisoning.—Acetylene may be fatally poisonous when present in proportions as high as 40 per cent. by
volume, as recently shown by Grehant, Berthelot, and Moissant. A mixture of 20 volumes of acetylene—prepared from calcium carbide, 20.S volumes of oxy gen, and 59.2 volumes of nitrogen—was breathed by a dog for thirty-five minutes without any marked disturbance, and 100 cubic centimetres of the blood were found to contain 10 cubic centimetres of acetylene. With 40 volumes of acety lene, the proportion of oxygen remain ing the same, a dog died in less than an hour, owing to failure of the heart's action, and 100 cubic centimetres of blood contained 20 cubic centimetres of acetylene. With 79 volumes of acety lene and 21 volumes of oxygen the poi sonous effects were still more strongly marked.
The poisonous action of acetylene it self is feeble when the blood is at the same time supplied from the air with the usual amount of oxygen. In other words. acetylene inhaled in the open air is but slightly harmful.
One hundred volumes of blood dissolve about eighty volumes of acetylene; the solution shows no characteristic spec trum, and is reduced by ammonium sul phide as readily as ordinary arterial blood. In a vacuum part of the acety lene is evolved at the ordinary tempera ture and part at 60° F. If the blood is allowed to putrefy, the volume of acety lene given off at the ordinary tempera ture remains practically the same, but the quantity liberated at 60° decreases as putrefaction advances. If any com pound of acetylene and hsemoglobin is formed, it is very unstable, and is not analogous to carboxyhannoglobin. Bro ciner (Boston Med. and Surg. Jour., July 30, '96).
In a closed room, however, where the oxygen is not kept up to the normal standard, when the accumulation of a foreign gas would prevent the constant renewal of air through window and door interstices or open chimneys, and where the products of respiration would be allowed to accumulate, it would quickly prove mortal by paralyzing the respira tory function.