Bacteria in Daily Life

by Grace C. Frankland

Now Koch's method for the compassing of rinderpest differed from both the systems above mentioned, inasmuch as he neither employed artificially weakened cultures of the virus, or an anti-toxic rinderpest-serum; instead he took one of the natural secretions of an animal infected with rinderpest, and by injecting this into a healthy animal it was discovered that the latter, as is the case with a vaccine, suffered only local and temporary discomfort, and acquired pronounced immunity from the active virus. The secretion selected by Dr. Koch and his assistant, Dr. Kolle, for this purpose was the gall, and it might be supposed, from the fact that its inoculation into healthy animals did not communicate the disease, that the rinderpest bacteria were absent from the gall. But this is not so, for Dr. Kolle has succeeded in isolating the latter from the gall of infected animals, and, moreover, has proved them on isolation to possess their full complement of virulence. Further investigations made by Koch and Kolle have shown that the explanation of this seeming anomaly is to be found in the fact that the gall of an animal suffering from rinderpest contains a substance which prevents the migration of the rinderpest bacteria, with which it is associated, from the point of inoculation. Hampered in their movements by the controlling influence of this special substance which has been generated in the gall, the bacteria remain rooted to the spot where they are first situate, and only a passing and exceedingly slight local affection results, which on its departure leaves the animal with an immunity from rinderpest lasting some four months. A number of interesting investigations have not unnaturally been stimulated by this remarkable discovery, and researches on the properties inherent in the gall of healthy animals of various kinds have been recently carried out by Dr. Neufeld, of the Institute for Infectious Diseases in Berlin, which are, however, of a too technical nature to deal with here.

As an illustration of the practical use to which Koch's gall immunisation method may be put in dealing with outbreaks of rinderpest, reference to a recent report furnished by the Health Officer of Shanghai may be of interest. Dr. Arthur Stanley describes the outbreak as follows:—

"A large herd of cattle infected with cattle-plague was brought to Shanghai from the Tanyang district, around the Grand Canal, for export to the allied troops in the north of China. The disease spread to an adjacent dairy, most of the cattle dying. On this dairy becoming infected a police cordon was established round it to prevent ingress and egress of cattle and ingress of persons unconnected with the dairy, while the outside infected herd was removed to an isolated part of the settlement. Having been previously convinced of the futility of police cordons in the prevention of cattle-plague, I was not surprised to find, within a short time, that the disease had spread, by the meeting together of cattle-coolies at a common tea-house, to three other dairies at a distance of a quarter, a half, and two miles from the original source of infection.

"As the animals are not, as a rule, taken away from the immediate vicinity of the dairy, there being no grazing fields, and as neither fodder nor dung is taken from one dairy to another, it is practically certain the infection was carried by the dairy-coolies.

"Immediately on this second series of dairies becoming infected it was resolved to apply the gall immunisation method of Koch as being the means at hand. About 1,500 cubic centimetres were collected from the gall-bladder of a rinderpest animal, and 10 cubic centimetres were injected into the dewlap of each of the twenty remaining cattle in the dairy.

"The injection caused slight local swelling and tenderness, but no constitutional symptoms and no alteration in the milk-supply, an important matter in a dairy. In all sixty-eight cattle were injected with cattle-plague gall. Of these, seventeen were among isolated uninfected herds; the remaining fifty-one belonged to infected herds, and among the latter eleven died of cattle-plague subsequent to the injection."

Dr. Stanley points out that ten of these animals, judging by the time which elapsed after the injection, when they showed the first symptoms of the disease, must have been already infected when the injections were made; the eleventh animal, however, undoubtedly contracted the disease after and in spite of the injection.

"Considering," continues Dr. Stanley, "the usual excessive mortality during an outbreak of this disease, the result may almost be compared to the success of vaccination against small-pox. Three young bullocks, each having received 20 cubic centimetres of cattle-plague gall, were purposely exposed to severe infection. They remained well, while unprotected animals around them died of the disease."

In the domain of immunity there is, however, no more fascinating or interesting story than that which deals with the discovery and elaboration of a cure for snake-bites, a discovery which, while attracting but comparatively little attention in this country, should prove of paramount importance to our fellow-subjects in the great Indian Empire. The significance to India of Professor Calmette's discovery of a specific cure for snake-poison may be gathered, indeed, from the statistics which have been compiled of the number of deaths attributed by Indian officials to this cause alone, amounting, it is said, to some 22,000 annually.

The Pasteur Institute in Paris has despatched many pioneers of science to various quarters of the globe, but perhaps no scientific missionary has produced more fruitful results than has Dr. Calmette. It was while acting in the double official capacity of Médecin de 1st Classe du Corps de Santé des Colonies and Director of the Bacteriological Institute of Saïgon, in Cochin China, in the autumn of 1891, that Calmette first commenced his experiments on the neutralisation of serpent venom in the animal system.