The explanation is pretty obvious; the mixture was alkaline, so that the strychnine was not in the form of a salt, but in the free state, and was therefore dissolved by the chloroform; the amount of strychnine taken in each dose wholly depended on whether or not the mixture was shaken violently and poured out into the teaspoon immediately after shaking; if allowed to repose the globules of chloroform saturated with strychnine would settle at the bottom, and there form a stratum rich in strychnine; so that the last dose would certainly contain an excess.
[434] White, Brit. Med. Journ., 1867.
[435] Folkes, Med. Times, 1869.
§ 393. Diagnosis of Strychnine Poisoning.—However striking and well defined the picture of strychnine tetanus may be, mistakes in diagnosis are rather frequent, especially when a medical man is hastily summoned, has never seen a case of similar poisoning, and has no suspicion of the possible nature of the seizure. If a young woman, for instance, is the subject, he may put it down to hysteria, and certainly hysteria not unfrequently affects somewhat similar convulsions. In a painful case in which the author was engaged, a young woman either took or was given (for the mystery was never cleared up fully) a fatal dose of strychnine, and though the symptoms were well marked, the medical attendant was so possessed with the view that the case was due to hysteria, that, even after making the post-mortem examination, and finding no adequate lesion, he theorised as to the possibility of some fatal hysteric spasm of the glottis, while there was ample chemical evidence of strychnine, and a weighable quantity of the alkaloid was actually separated from the contents of the stomach. The medical attendant of Matilda Clover, one of Neill’s victims, certified that the girl died from delirium tremens and syncope, although the symptoms were typically those produced by strychnine. Such cases are particularly sad, for we now know that, with judicious treatment, a rather large dose may be recovered from.
If the case is a male, a confusion with epilepsy is possible, though hardly to be explained or excused; while in both sexes idiopathic tetanus is so extremely similar as to give rise to the idea that all cases of idiopathic tetanus are produced by poison, perhaps secreted by the body itself. As for the distinction between idiopathic and strychnic tetanus, it is usually laid down (1) that the intervals in the former are characterised by no relaxation of the muscles, but that they continue contracted and hard; and (2) that there is a notable rise of temperature in disease tetanus proper, and not in strychnine tetanus. Both statements are misleading, and the latter is not true, for in strychnic poisoning the relaxation is not constant, and very high temperatures in animals have been observed.
§ 394. Physiological Action.—The tetanic convulsions are essentially reflex, and to be ascribed to a central origin; the normal reflex sensibility is exaggerated and unnaturally extended. If the ischiatic plexus supplying the one leg of an animal is cut through, that leg takes no part in the general convulsions, but if the artery of the leg alone is tied, then the leg suffers from the muscular spasm, as well as the limbs in which the circulation is unrestrained. In an experiment by Sir B. W. Richardson, a healthy dog was killed, and, as soon as practicable, a solution of strychnine was injected through the systemic vessels by the aorta—the whole body became at once stiff and rigid as a board. These facts point unmistakably to the spinal marrow as the seat of the toxic influence. Strychnine is, par excellence, a spinal poison. On physiological grounds the grey substance of the cord is considered to have an inhibitory action upon reflex sensibility, and this inhibitory power is paralysed by strychnine. The spinal cord, it would appear, has the power of collecting strychnine from the circulation and storing it up in its structure.[436]
[436] R. W. Lovett, Journ. Physiol., ix. 99-111.