THE POPULAR SCIENCE MONTHLY.
familiar chemical methods, and that conferred the power of resisting the living micro-organism.
During the epidemic in Spain, Ferran's inoculations were practiced in more than thirty thousand persons. In the province of Valencia there were 62·33 cases per thousand of population, and 31·11 per thousand died of cholera. Where inoculation was generally practiced the cholera affected 76·95 per thousand, with a mortality of 33·58, of the total uninoculated; while among the inoculated 12·69 per thousand were attacked, and only 3·41 per thousand died. In other words, in the latter class 6·06 times fewer people were attacked, with a mortality 9·84 times less than that of the uninoculated.
Ferran's methods were investigated by commissions from several of the European scientific societies; and by several, notably that from France, he was condemned for having made claims that could not be demonstrated.
In 1888 Dr. Gamaleia published the results of experiments he had made with the cholera spirillum. He found that the cultures of this organism, as obtained from the human body, lose their virulence in the laboratory. In order to restore this virulence, and possibly to enhance it, Dr. Gamaleia first inoculated a guinea-pig with the cholera spirillum, and when the disease was apparent in that animal made an inoculation from it into a carrier-pigeon. This was on the principle employed by Pasteur to increase or attenuate the virus of chicken-cholera, rouget, anthrax, and rabies by inoculating different animals with the respective virus of those diseases. So toxic does the cholera spirillum become in the pigeon, that a few drops of its blood rapidly kill an animal susceptible to cholera. He also found that in a sterilized culture of the spirillum there was a principle that, administered in non-toxic doses to an animal, would afford subsequent protection from cholera. The phenomena produced by these inoculations were similar to those observed by Ferran in his own experiments, though no inoculations were made in man by Gamaleia. G. Klemperer has reported this year experiments that verify those made by Ferran and Gamaleia. He discovered that a guinea-pig could be protected against cholera by inoculating it with the serum of the blood of a rabbit that had been protected by inoculation of mild cultures of the spirillum; and in one rabbit that had been rendered immune to pneumonia as well as to cholera, its serum afforded protection from cholera to guinea-pigs, and from pneumonia to mice. He considered that these results corresponded with the immunity observed in human beings after an attack of Asiatic cholera.
During this year Haffkine has reported to the Paris Biological Society experiments that he has made with the spirillum.