Direct infection from man to man does probably occasionally occur, but the contingency is too remote an one to be worthy of consideration, as it implies close personal contact, and in fact is usually traceable to those in attendance on the sick getting their hands or clothing fouled with the discharges and neglecting due measures of disinfection before eating or drinking. Save in this way, there is practically no risk whatever in the proximity of, or of attendance on, cholera cases, and no one need shrink from nursing persons stricken down with the disease, provided they observe a few very obvious precautions. Fortunately the cholera germ is rather a delicate sort of plant, and but for its sharing with man a preference for good drinking water it would be comparatively harmless, as it soon perishes elsewhere, and is very soon destroyed by drying or too great heat. It is needless to remark that it cannot stand boiling, for the germs that can stand that sort of treatment are few and far between; but it is also very sensitive to the action of most of the ordinary disinfectants, which destroy it in dilutions far weaker than is the case with the agents of most other diseases; and it is also killed by a sufficiently long exposure to the action of carbonic acid, from which fact there outcomes the useful bit of knowledge that it is quite safe, _qua_ cholera, to drink aerated waters even of doubtfully careful preparation, provided that they have been kept a few days in the house before use. Owing to the fact that the cholera germ cannot only survive, but is also capable of multiplying, in drinking water of average purity, the amount of fouling of the water which is required to infect it may be very small indeed, and usually is infinitesimally small.