Opinions are at present divided as to whether the anæsthesia produced by Cocaine is the result of vasomotor disturbance—the small vessels are caused to contract by its application, and the nervous filaments are doubtless anæmic—or whether Cocaine acts directly as a paralyser on the nervous endings, whether of sensibility, or touch, or of special sense, since it removes the power of taste and smell, as well as the perception of touch and pain. When Cocaine is administered in such a dose and manner as to affect the whole system, the brain seems to become excited, the heart stimulated, and blood and pressure increased. Poisonous doses kill by asphyxia, the breathing becoming arrested and the heart failing in diastole; but this has not yet been observed in man, the dose necessary to produce this effect being very large; 20 grains have been taken without very serious result. It diminishes all the secretions, and, although the intestinal movements are slightly stimulated at first, larger doses or continued use cause sluggish action, dyspepsia, and constipation. Tissue change is lessened, and the amount of urea is similarly diminished; the temperature seems to be somewhat higher than normal; albuminuria has been found to follow its use, and sugar has been found in the urine. The kidneys are probably the special means of its elimination. With regard to its action on muscular fibre nothing is known, observers being completely at variance in their opinions.—Buxton, in Ringer’s “Therapeutics,” 12th edition.
“Brown-Séquard regards the effect as a new sample of inhibitory action, his experiments convincing him that Cocaine acts through the medium of the peripheral nerves on the nervous centres, which react in bringing about inhibition of sensibility. The phenomena which result from the injection of Cocaine at the level of the larynx, he finds to be the same as those which are consecutive to the application of a jet of carbonic acid on the mucous membrane of that organ. Two minutes after the injection there is a generalised anæsthesia and an analgesia of the different wounds made on the body of the animal. The cutaneous anæsthesia lasts only a few minutes, but the analgesia of the wounds persists even till the following day. If fresh wounds are made, these, far from being analgesic, become, on the contrary, hyperalgesic. That which proved that Cocaine acts on the nervous centres, and particularly on the cerebellum, is that injections of this substance produced sometimes a rolling motion to the side opposite to the injection, and at others a turning motion. Evidence of the inhibitory action is offered by another of Brown-Séquard’s experiments: when the dose of Cocaine injected was large enough to produce convulsions, it was sufficient to pull or forcibly flex the toes to immediately stop the convulsions. In animals which died under these conditions the temperature of the body after death was as high as 44°·4 C, or 111°·6 F.”—Brown-Séquard in Prosser James’ “Guide to New B.P.”
In Vienna, Cocaine has been recommended for use internally in cases of great exhaustion, such as loss of blood, sunstroke, or diarrhœa, also by mouth or hypodermically as a cure for morphine and alcohol craving. Morphine and Cocaine appear to be mutually antagonistic. Cocaine has been used in some cases of melancholia and insomnia; it also possesses aphrodisiac properties. It was likewise found to lessen the desire for sleep and feeling of hunger, and to be a stimulant which quickly increases and sustains, in a harmless manner, the physical powers of the body, such as are required in long marches, mountain ascents, &c., in dose of ¾ to 1½ grains.
Cocaine is a stomachic, useful after excess either in eating or drinking, in distaste for food, in sea-sickness and vomiting of pregnancy, or from other causes; it also improves the condition of the stomach in atonic indigestion and nervous affections of this organ, as well as in phthisis and cachectic cases, especially those arising from the use of mercury.
CHAPTER XVI.
MEDICAL NOTES AND REFERENCES.
Cocaine is a mydriatic; slightly raises the temperature, quickens respiration, and pulse is more frequent; by long use, sleep is longer and more profound. Improves nutrition, useful in insomnia and simple melancholia.—M.R. 1883, 86.
Eleven successful cases, including three of operation for cataract, one double iridectomy, one removal of tumour from lid, and three for convergent strabismus. In cases of intolerance of light it acts like magic.—L. ii./84,911.
In papillomata of larynx, interior painted with 20 per cent. solution of hydrochlorate of Cocaine once, in five minutes was able to introduce the forceps four times and remove large portions of tumours without patient experiencing any pain or subsequent shock.—L. ii./84,912.
In quinsy, a 20 per cent. solution useful to paint fauces.—Pr. xli. 47.
Coca and Cocaine are said to have a deleterious action on the voice, slackening and deadening the vocal cords through the paralysis of the extensor muscles. The aphony produced is painless.—Th. Gaz. May, 1889,353.