Treatment by brain emulsion. Wassermann and Takaki (Berlin Klin. Woch. Jan. 3d, 1898) have in a number of cases, mixed 1cc. of brain substance of a warm-blooded animal with ten times the lethal dose of tetanus toxin and injected without producing any symptoms of tetanus. They obtained a similar immunity by injecting the brain emulsion 24 hours after the injection of three times, and in other cases of five times the lethal dose of tetanus toxin. Control cases uniformly died of tetanus. The brain matter was obtained from Guinea pigs, pigeons, rabbits, horses, and men. They accordingly advanced the theory that brain matter is a direct antidote to the tetanus toxin, uniting with it chemically and rendering it innocuous. The liver, spleen, kidney, bone marrow and blood serum gave no such protection.
Marie, in a series of experiments, injected the brain emulsion and tetanus poison at different parts of the body of Guinea pigs and found that fatal tetanus ensued. It would appear, therefore, that the brain emulsion acts by direct contact, and that it is only by its meeting and combining with the toxin before the latter reaches the spinal cord that tetanus can be prevented.
Roux and Borrel (Ann. de l’Instit. Pasteur, 1898) demonstrated this union between the poison and brain matter, by making an emulsion of the two, and putting in a centrifuge, which will separate the brain substance from the clear liquid. The fluid obtained in this way was shown by injection on the living animal to contain almost no toxin. Knorr and Blumenthal reached the same conclusion as to a chemical union with the brain matter which robbed the toxin of its toxicity.
Knorr, and Tizzoni, and Cattani and Morax showed indeed, that if the tetanus toxin is injected subdurally or into the surface layers of the cerebrum, it produces not tetanus, but a characteristic cerebral disease. A dose of ¹⁄₂₀th or ⅒th cc. of tetanus toxin produces in the rabbit, in 10 to 12 hours, restlessness, constant change of place, and signs of great fear like hiding the head, turning rapidly round, attempting to escape, polyuria, grinding the teeth, epileptoid convulsions. The toxin in this case had manifestly united with the brain substance while the cord suffered little.
Metchnikoff (Ann. de l’Inst. Past., April, 1898) holds that the brain matter is only valuable in holding the toxin until it can be destroyed by the leucocytes. He showed that the injection of the tetanus toxin in chickens or Guinea pigs greatly encreased the production of leucocytes. He injected tetanus toxin into the aqueous humor of the rabbit without producing much effect, but when the same agent mixed with cerebral substance was injected, the result was a great accumulation of leucocytes, and hypopion. If the mixture of brain substance and tetanus toxins were injected on the brain, little encrease of leucocytes occurred, but if thrown into the peritoneum, a most remarkable leucocytosis took place. In twenty minutes after the injection the fluid withdrawn from the abdomen showed large numbers of leucocytes filled with brain substance, but no free cerebral matter.
The present status of the treatment by brain substance is therefore somewhat uncertain. The value of that agent in holding the toxin is allowed, but like the antitoxin it must be employed before the toxin has reached the nerve centres and united with the living ganglion cells. Its use would be called for therefore at the earliest possible moment and it should be continued so long as there is reason to suspect the production of fresh toxin in the wound. Its direct action on the toxin would suggest its injection around an infected wound, or even as a dressing for the wound in connection with antiseptics. When tetanus has already set in it cannot be expected to undo the evil already accomplished by the union of the toxin with the cells of the cord, though it might in part arrest and hold new supplies of this poison coming from the wound to the nerve centres.
Prevention. In a disease so deadly as tetanus and so refractory to treatment even by antitoxin when it is once developed, prophylactic measures are of the greatest importance. With the extensive adoption of antiseptic surgery there has already been a material diminution in the number of cases, yet a greater attention is demanded to the prevention of casual cases which result from ordinary wounds. Dirty, grimy wounds filled with the dust of stable yard or garden soil, and such as contain splinters of wood, stones, thorns, straw and the like can only be considered quite safe after thorough disinfection. It has been shown that the toxin is easily neutralized at the time of infection, whereas, after the disease is developed it will require 1,000 or 100,000 times as much antitoxin to produce the same effect. In the case of soiled wounds, therefore, in a valuable animal, a harmless injection of antitoxin or of phenic acid or iodine solution before the development of tetanic symptoms is not an unwise precaution. A succession of such injections might be given to ward off the disease until after a lapse of time exceeding the short and dangerous incubation.
Much more important is the disinfection of the wound itself. All foreign bodies must be removed, but especially those that like splinters of wood and straws are likely to harbor the spores of the bacillus. Then the wound may be thoroughly cauterized thermically or chemically, or it may be irrigated with a strong antiseptic solution and then dressed with some agent that will prove destructive to the spores, and antidotal to the toxin. Strong carbolic acid may be applied to the whole raw surface including the uttermost recesses of the wound, and after a few seconds or half a minute this may be neutralized by filling the wound with dilute acetic acid or alcohol, after which a dressing of Lugol’s solution may be applied. Lambert advises a combination of hydrochloric and carbolic acids.
Weaker antiseptics, like a 5 per cent. solution of carbolic acid, do more harm than good, as they destroy the pus and saprophytic microbes and even the tetanus bacillus in the wound, without affecting the tetanus spores, which finding no other microbes to contest with them the possession of the field may find themselves in a better position than before to develop into bacilli and cause tetanus.
Tetanus neonatorum may be certainly prevented by the application of a disinfectant plaster on the navel at birth. Over 50 years ago in Scotland this desideratum was met by applying on the navel of the new-born child a soft and immaculately clean piece of cotton cloth which had just been flamed over a light. On the island of St. Kilda the former mortality of 67.2 per cent. of new-born infants, was promptly abolished by dressing the navel daily with iodoform. For new-born animals a cheap and convenient application may be made by incorporating 1 oz. powdered iodine and 2 lbs. wood tar, and smearing this on the navel.