Of course, the preventive treatment touches points only here and there on the map of India, with its 300,000,000 people. Probably it will never become so general in India as vaccination. Cholera in India recalls what Ambroise Paré, more than 400 years ago, wrote of the plague, "Here in Paris it is always with us." But, wherever preventive inoculation has been done, there it has done good.
The Medical Annual for 1905 contains an account of some preventive inoculations recently made during an epidemic in Japan. Among the inoculated, the attack-rate was much lower than among the uninoculated; and the mortality was 45.5 per cent., as against 75 per cent.
Another most important result of the discovery of the cholera bacillus is its use in diagnosis. For example, if a case of suspected cholera is landed at a British port, the sanitary authority at once takes steps to ascertain whether the specific microbe is present; and, according to the answer given by bacteriology, either allows the patient to proceed on his journey, or adopts measures of isolation to prevent the spread of the disease to others. Thus, thanks to the insular position of Great Britain, this dreadful disease has for many years been prevented from invading her population.
VIII
PLAGUE
The bacillus pestis was discovered by Kitasato and Yersin, working independently, in 1894. Yersin's discovery was made at Hong Kong, whither the French Government had sent him to study plague: an excellent account of his work is given in the Annales de l'Institut Pasteur, September 1894. The first experiments in preventive inoculation, in animals, were made by Yersin, Calmette, and Borrel, working conjointly, in 1895. They found that it was possible to confer on animals a certain degree of immunity, by the hypodermic injection of dead cultures of the bacillus. These experiments were made on rabbits and guinea-pigs.
Haffkine's fluid was first used on man in January 1897. It is a bouillon containing no living bacilli, and nothing offensive to the religious beliefs of India.[33] He proved its efficacy on rabbits; and then, on 10th January 1897, inoculated himself with a large dose, four times as strong as the subsequent standard dose. A few days later, Lieut.-Col. Hatch, Principal of the Grant Medical College, Bombay, and other members of the College Staff, were inoculated. These first inoculations were described by Haffkine in a lecture (1901) at Poona:—
"In a short time, a number of the most authoritative physicians in Bombay, European and native, official medical officers and private practitioners, submitted themselves for inoculation. It is a matter of gratification to me to be able to quote, among these authorities, the Head of the Medical Service of the Presidency, Surgeon-General Bainbridge, who not only got himself inoculated, but inoculated also the members of his family. Previous to that, Surgeon-General Harvey, the able Director-General of the Indian Medical Service, submitted himself to inoculation in 1893 against cholera; and, in 1898, against plague. It was the example of these gentlemen, whose competence in the matter of health could not be disputed, that encouraged thousands of people, rich and poor, in Bombay and elsewhere, to come forward for inoculation. Thus his Excellency the Viceroy thought it right to tell you here, in Poona, that previous to his starting for the plague-stricken districts he and his staff had also undergone the prophylactic inoculation. In due course, mothers brought their children to be protected by the new 'vaccination.'"
Within a few months, 8142 persons in or near Bombay were inoculated. It was not possible, in Bombay, during the rush of plague-work, to follow up every one of these 8142 persons. But there is reason to believe, making some allowance for oversights, that only 18 = 0.2 per cent. of them, were attacked during the epidemic; that, of these 18, only 2 died: and that these 2 died within twenty-four hours of inoculation, i.e., had the plague in them already at the time of inoculation.
And, with regard to a small group of the inoculated, there are the following more definite facts. This group lived outside Bombay, across the harbour, in a village called Mora. The population of Mora, at the time of the epidemic, was estimated at less than 1000. Out of this number 429 were inoculated; which, if the population be reckoned at 1000 exactly, left 571 uninoculated. Among the 429 inoculated, there were 7 cases of plague, with no deaths: among the uninoculated there were 26 cases, with 24 deaths.
Just a week after Haffkine had informed the Indian Government that he had tested his fluid on himself, plague broke out in the Byculla House of Correction, Bombay, on 23rd January 1897. Between the 23rd and the afternoon of the 30th, there were 14 cases, with 7 deaths. On the afternoon of the 30th, 152 prisoners were inoculated, and 172 were left uninoculated. The outbreak ceased on 7th February. The figures, as corrected by the Plague Commission, are, among the inoculated, 1 case, which recovered; among the uninoculated, 7 cases, with 2 deaths.