Pyridine is a volatile liquid, having a strong, diffusive, and somewhat aromatic odor. Its vapor is given off at ordinary temperatures, and its therapeutical effects are obtained by inhalation. We owe the valuable suggestion of its inhalation for certain purposes to Prof. Sée, who ascertained that it acts on the reflex function of the cord, and also on respiration. The special purpose for which it is prescribed is the treatment of asthma, and this condition is relieved, what cause soever may have developed it. The manner of its employment is simple: it consists in placing a saucer containing some pyridine (3 j, for example) in a large closet or small room that can be tightly closed, the patient remaining in it for twenty to thirty minutes, and repeating the same procedure two, three, or five times a day as may be necessary. In simple asthma a cure may be effected in ten to thirty days, and in symptomatic asthma, emphysema, etc., remarkable relief is obtained. Prof. See does not advise pyridine as the sole remedy, for the iodides constitute the true curative means, in his belief.

With the inhalation of pyridine vapor can be combined ethyl iodide, the latter contributing the iodine which is so effective of itself in many cases of asthma.

Pyridine has basic properties, and forms crystallizable salts with acids, which, however, are somewhat unstable. It mixes with water in all proportions, but, as it is exceedingly volatile, should be prepared as required. The dose for internal use is from five to twenty minims. Exhibited in this way, it increases the power of the cardiac contractions, raises the tension, and greatly lessens respiratory embarrassment. Its action resembles that of digitalis, for which it may often be substituted with distinct advantage (De Renzi). The salts can be used in lieu of the volatile pyridine in many cases.