An important, but still undecided question is, whether the action of strychnia takes place directly upon the nervous tissues, or whether the nervous phenomena are only secondary to a general blood-poisoning. Dr. George Harley, some years ago, published an opinion, based upon experimental researches, to the effect that the nervous phenomena are due to the influence of the blood, the oxidation of which was believed by him to be suddenly arrested by the action of strychnia, as well as by that of several other poisons. So far as I am aware, this opinion has not gained ground in recent years. That strychnia, however, is in part chemically changed within the blood can hardly be doubted; for although it has been detected by various observers in the urine of animals poisoned by it, the quantity so found is not sufficient to account for the possibility of those occasional recoveries after large doses which have been observed. Some of these were, no doubt, merely examples of non-absorption, a large part of the strychnia having passed away with the stools, without ever having entered the blood. But this will by no means account for all the facts; and on the whole it seems probable that a portion of the alkaloid is destroyed by oxidation within the blood. It is much more difficult to accept Harley's opinion that the deoxidation of the blood accounts for the nervous symptoms; for upon that theory it seems inexplicable that the spinal cord should be so exclusively affected with the graver symptoms, and the brain be not disturbed in any high degree.

Strychnia has been proved (by Binz and others) to possess in a hum bler degree the influence which quinine so powerfully exerts as a poison to the leucocytes, and also to various lowly-organized animal and vegetable organisms - a fact which it will be advisable to bear in mind in future attempts to extend the therapeutic applications of this alkaloid.

Lastly, it must be remembered that strychnia in concentrated solution is capable of acting as a direct irritant. It is possible that a part even of the nervous phenomena of ordinary strychnia-poisoning are reflex effects of stomach-irritation; but, at any rate, the singular facts brought to light by Mr. Barwell's plan of injecting the alkaloid into the substance of paralyzed muscles (to be presently noticed) is conclusive as to its irritant qualities.

(Physiological Action of Brucia. - Like strychnia, brucia produces a condition of exalted reflex irritability with convulsions, the only difference so far discovered being that larger doses of brucia are required to produce the same effects. The iodide of methyl-brucia, discovered by Stahlschmidt and the sulphate of methyl-brucia appear to produce an opposite condition, namely, diminution of reflex irritability and paralysis of motor nerves, similar to the condition induced by Curara.)

Therapeutic Action. - There are few medicines which have more remarkable therapeutic power than nux-vomica and strychnia, and few that have been more abused and misapplied, considering the short time during which they have been known to medical men.

The actions of nux-vomica and of strychnia so essentially correspond, that it is only necessary to say a few words about the former. Its employment in any case, in preference to strychnia, is purely a matter of convenience: the extract of nux-vomica is a convenient form, for example, for making into pills, while the tincture can be readily subdivided into doses representing extremely small quantities of strychnia. The latter is an especially favorite form for administration in certain complaints of children presently to be mentioned.

In Paralysis. - The earliest applications of strychnia in medicine were naturally directed to the cure of paralytic affections, and during some years it was employed very indiscriminately, and often in far too large doses. Those who prescribed it entertained the idea that the use of the drug should be pushed to a point at which actual symptoms of poisoning commenced: acting upon this impression, doses as high as the 1/8 and 1/4 grain, twice or three times a day, were often reached, with the almost invariable result of throwing the patient's nervous system into great disorder, manifested by twitchings of the limbs, hyperesthesia of the retina and the auditory nerve, and a state of perpetual restlessness. It was discovered after a time that such effects were always injurious rather than useful: but it has further been found that violent strychnia-action is specially hurtful, and that the drug in any dose is valueless in particular forms and stages of paralysis. In paralysis of cerebral origin it is seldom of any value, and, on the other hand, its too early use in these affections, especially in such as proceed from haemorrhage, has often proved very mischievous. It would be natural to expect better results from its employment in spinal paralysis, yet even here there is frequent disappointment, and in the early stages of organic lesions it often does much harm, especially if given in large doses. In the so-called "reflex " paralysis, it was supposed (by Brown-Sequard especially) to promise great results, but experience has hardly supported these expectations - a result, perhaps, not surprising, since the tendency of recent pathology is to render it probable that in these cases there is actual myelitis, produced by irritation transmitted to the cord through the nerves of the kidney, bladder, uterus, or whatever organ it may be in which the original mischief existed. In functional paralysis, on the contrary (e. g., hysterical), strychnia is often of use, and decidedly promotes the recovery of power by muscles which have been paralyzed by the influence of lead. Brown-Sequard more correctly states that strychnia ought to be avoided as a most dangerous poison in those cases of paraplegia in which there are signs of congestion or inflammation of the spinal cord or of its membranes. For my own part, I think it is fully established that strychnia should not be employed except in cases where the symptoms are chronic, and thoroughly free from acute congestion.