Bacteria in Daily Life

by Grace C. Frankland

It is interesting to note that, although diluted eel serum can protect an animal from so deadly a poison as viper venom, the serum of vipers is quite unable to afford any such service in the case of animals inoculated with ordinary eel serum. The full complement of protective power obtainable from this treated eel serum is only able to slowly assert itself, for it is necessary for a period of as long as twenty-four hours to elapse after its introduction to ensure the animal's system being thoroughly impregnated with it and enable it to withstand a lethal dose of viper venom.

In this respect, what may be designated treated or protective eel serum differs very markedly from anti-venomous serum, which we have seen is serum derived from animals trained up to withstand fatal does of serpent venom, for anti-venomous serum acts immediately, and at once confers immunity on an animal from the lethal effects of such venom.

The rapidity with which it acts is indeed one of the most astonishing properties of this particular anti-toxin. Thus if two cubic centimetres of anti-venomous serum be inoculated into the marginal vein of a rabbit's ear, it at once confers upon the latter complete immunity from snake poison. Immediately after the injection of the serum, venom sufficient to destroy an ordinary rabbit in a quarter of an hour may be injected with impunity into the vein of the other ear. But not only are the protective powers of this serum so remarkable in their degree, but its curative powers, a much more difficult property to establish in a substance, are extraordinarily intense, as may be gathered from the following example. Four rabbits were inoculated with a quantity of venom calculated to destroy them in the space of two hours; one of these four animals was abandoned to its fate, but the other three received, practically at the eleventh hour, viz. just fifteen minutes before the expiration of the calculated two hours' respite, an intravenous injection of a small quantity of anti-venomous serum, only amounting to one four-hundredth part of the weight of each animal respectively. The rabbit which received only the venom died at the end of two hours, whilst the other three remained in perfect health.

But although eel serum can be persuaded to part with its poisonous character and even exercise protective powers over otherwise doomed victims, it is not able to stretch forth a healing hand to the afflicted, for, when once the poison has been introduced, whether it be eel or viper blood, or the venom of snakes, it is absolutely powerless to mitigate or stop in any way the deadly progress of the toxin. Thus whilst eel blood may acquire protective properties it cannot acquire curative properties, and, therefore, treated eel serum cannot be legitimately enrolled with the anti-toxins which have been elaborated, as, for example, anti-venomous serum, for, to be worthy of such rank, a substance must be capable of wielding both protective and curative powers.

But, although eel serum may under certain conditions protect from the lethal action of serpent venom, eels are not themselves under ordinary circumstances endowed with any power to withstand the influence of this poison, for a good-sized eel will succumb to a dose of venom which is sufficient to kill a guinea-pig.

Considerable interest is attached to the fact that anti-venomous serum not only acts as an anti-toxin towards serpent venom, but also towards a poison of quite a different character, such as that present in the normal blood of eels, for this fact tends to confirm the view upheld by some authorities, that specific toxins do not necessarily only yield to specific anti-toxins, and that a particular anti-toxin may act as such towards divers toxins of varied origin and character. Calmette has brought this point out very clearly in his later investigations on the vegetable poison abrine, a very powerful toxin, furnished by the active principle of the seeds or beans of a leguminous plant common in India and South America, and frequently used, as already mentioned, by the natives in India to revenge themselves on their enemies in poisoning their cattle. Immunising serums of various kinds were selected for testing their protective action on animals poisoned with abrine, and it was found that anti-tetanic, anti-diphtheritic, anti-anthrax, and anti-cholera serums all individually exerted a decided immunising action with regard to this powerful vegetable poison. The hope is, therefore, perhaps not beyond the realm of possibility, that at some future time the complexity of drugs which now figure in the chemists' pharmacopœia may be replaced by a few substances the application of which will come within the means and understanding of all. So far we have not dealt with the artificial immunisation of an animal from the action of eel poison, but this apparently offers very little difficulty, and is accomplished by introducing very small and gradually increasing doses of eel serum into the system, care being taken to proportion the quantity given according to the weight and general condition of the animal to be immunised. A rabbit, for example, treated in the above manner, subsequently yielded a serum which was proved to possess both preventive and curative powers in respect to both eel poison, and viper venom and blood, entitling this so called anti-eel serum to take its place amongst the anti-toxins, and furnishing yet another instance of a substance exercising its immunising influence over various toxins.

This process of gradually acclimatising, as it were, animals to a particular poison by repeated doses of the same poison, recalls the old proverb, "Seek your salve where you got your sore," and brings us to a consideration of some of the primitive antecedents of a practice which, at the present time, promises to bring about so profound a revolution in the art of medicine. The modern system of inoculation has, however, arisen quite without reference to such antecedents, which latter were not based upon any scientific laws or considerations, but owed their evolution to local customs and experience handed down from age to age by tradition, and in many cases preserved through a simple faith in the superstitions which surrounded them.

To such a category must be added the curious superstitions indulged in by the native population of Tunis regarding methods of preventing hydrophobia in persons bitten by rabid animals. Dr. Loir refers to these primitive ideas on the art of healing in a report of the work carried out at the Anti-rabic Institute at Tunis, one of the many centres for the prevention of rabies by Pasteur's method which have been established in every quarter of the globe except Great Britain, the inhabitants of this "great conservative island-Empire," as a renowned foreign scientist describes it, still preferring a trip to Paris to countenancing the establishment of an anti-rabic institute in their own country. The Arab physicians in Tunis have from time immemorial sought to specially identify themselves with cures for this disease, which is so prevalent as to be a veritable scourge to the country. A much-vaunted remedy advocated by the profession consists in pounding up the charred head of a rabid dog with vinegar, and administering an emulsion of the same to the patient. The dung of camels is also highly prized as a remedy, as also the water of certain wells which the simple faith of the natives has endowed with supernatural curative properties. But the strangest prescription of all consists in broth made from lambs a year old, to which is added a peculiar kind of beetle, but in such a small quantity that the latter ingredient only equals the weight of a grain of corn. This concoction is given to the unfortunate patient twenty-three days after he has been bitten. In the urine, according to the Arabian doctors, seven small worms should be found which represent the embryos of dogs engendered by the virus in the human body, and which when once got rid of the patient recovers!

In the face of such crude traditions upheld with so much tenacity by the native population, it is surprising that the Tunisian Anti-rabic Institute has met with such a large measure of support in the shape of applicants for admission, which, on an average, number over one hundred annually. The mortality amongst those treated closely approaches the satisfactory results obtained at the Paris Institute, where the death-rate amounts to about 0·38 per cent. of the persons treated.

There is perhaps no more interesting chapter in the history and literature of medicine than might be compiled by searching out the early uses of drugs and the primitive application of methods in the art of healing, and tracing their connection, if possible, with the practices which are in vogue at the present day. In the matter of toxins and anti-toxins, or in respect to the modern theories of preventive medicine, there would appear to be a curious link between the methods based upon elaborate scientific inquiries and those which arose through simple experience and expediency.