With respect to the cause of cholera, I may mention decomposed and decomposing animal and vegetable matter in drinking water, but whatever may be the essential cause or causes of cholera, I must leave for some future discussion. What is of the most practical value to know is, that the laws which govern the endemic influence of cholera, are as well known as those of typhoid fever, and equally under our control. Those conditions which are favourable to the spread of typhoid fever, are equally favourable to the spread of cholera when once it shows itself, and the same sanitary regulations which are applicable to typhoid fever, are best calculated to prevent and control cholera. The following suggestions may be observed with advantage to the sick, and those connected with them:— 1. In cases of contagious diseases _fresh air_ is of primary importance to both patient and attendant. The room should be well ventilated, care should be taken that no draught blows upon the patient, but a continual supply of fresh air enters the room. In cases where it is not expedient to have both window and door open a fire ought to be lighted, and the door kept open. A fire not only is a good means of ventilating a sick room, but it also dries the air and thus renders it a less susceptible medium for carrying and retaining infectious poisons. 2. Cleanliness is very desirable in health, but it is imperatively necessary in disease, both the room and the patient should be kept thoroughly clean. Both body and bed linen should be frequently changed, and as soon as the soiled linen is removed it should be placed in water and thoroughly washed, and not rolled up and kept till the regular washing day. There is a great objection to change the linen of patients suffering from fever for fear they should catch cold, this is an ignorant prejudice. Fever patients do not take cold if ordinary care be employed. The skin of fever patients not only becomes hot and uncomfortable but dirty. It is often advisable to sponge them with a little luke-warm vinegar and water. The room ought to be washed out daily, and thoroughly dried. It is useful to have a little of Condy’s disinfectant fluid in the water. All carpets, curtains, and woollen furniture is better removed out of the sick chamber. All discharges from the patient ought to be immediately emptied, and the utensils washed out with Condy’s fluid and water; and further, all water closets &c., ought, at these times, to be daily (at least) well flushed with water. 3. Nurses, relatives, friends, and visitors, ought to avoid breathing the patient’s breath, and ought not to remain in close proximity longer than duty requires. They should not swallow their spittle, and on leaving the sick chamber, they should clear their mouth and nostrils. Smoking is only of service in so far as it promotes expectoration; and snuff, only because it induces sneezing.