"Outside Calcutta, since the commencement of the inoculations in India in April 1893, opportunities for an exact comparison of the respective powers of resistance against cholera of inoculated and non-inoculated persons presented themselves; (1) in Lucknow, in the East Lancashire Regiment; (2) in Gaya, in the jail; (3) in Cachar, among the tea-garden coolies; (4) in Margherita, among coolies of the Assam-Burmah Railway Survey; (5) in Durbhanga, in the jail; (6) in the coolie camp at Bilaspur; (7) in Serampur, among the general population."
Here, then, in this 1896 report, are all the results that give an answer to the question, What will happen when cholera breaks out among a number of people living under the same conditions, of whom some have received preventive treatment, and the rest have been left to Nature?
I. Calcutta (1894-1896)
"The number of people inoculated during the period under review was 7690; of these, 5853 are Hindus, 1476 Mahomedans, and 361 other classes.... Considering that the system is a new one, that the inoculations are purely voluntary, and everything connected with them has to be explained before the confidence of the people can be obtained, and considering how long new ideas are in taking root among the general population—and in this case it is not merely the acceptance of an idea, but such faith in it as to consent to submit to an operation—the number is certainly satisfactory for a beginning. The present problem can be compared with the introduction of vaccination against smallpox into Calcutta. It took 25 years before the number of vaccinations reached an average of 2000; whereas the inoculations against cholera have in two years nearly doubled that average. This is a proof that, in spite of the difficulties which every new movement naturally has to meet with, there are large numbers of people anxious to avail themselves of the protective effect of the inoculations.
"Although all sorts and conditions of individuals, weak and strong, sickly and healthy, young and old, well nourished and badly nourished, and often persons suffering from chronic diseases, have been inoculated, in every instance, without exception, the inoculations have proved perfectly harmless.
"The investigations on the effect of the inoculation are made exclusively in those houses in which cholera has actually occurred, the object being to ascertain and compare the incidence of cholera on the inoculated and not inoculated in those houses in which inoculations had been previously carried out. For this purpose, affected houses in which inoculations have not been performed, and inoculated houses in which cholera has not appeared, are excluded."
Nature gave a demonstration in 77 houses. In one house, and one only, all the household had been inoculated; in 76, inoculated and non-inoculated were living together; but of these 76 houses, 6 are excluded from the table of results, because the inoculated in them were so few—less than one-tenth of the household—that their escape from cholera might be called chance. The cholera came, and left behind it this fact:—
654 uninoculated individuals had 71 deaths = 10.86 per cent.
402 inoculated in the same households had 12 deaths = 2.99 per cent.
If we add the 6 houses which Dr. Simpson excludes, we find that in 77 houses there were 89 deaths from cholera, 77 being among the uninoculated and 12 among the inoculated.