The mode of communication of cholera might have been the same as it is, even if it had been a disease of the blood; for there is a good deal of evidence to show that plague, typhoid fever, and yellow fever, diseases in which the blood is affected, are propagated in the same way as cholera. There is sufficient evidence also, I believe, in the following pages, to prove the mode of communication of cholera here explained, independently of the pathology of the disease; but it was from considerations of its pathology that the mode of communication was first explained, and, if the views here propounded are correct, we had a knowledge of cholera, before it had been twenty years in Europe, more correct than that of most of the older epidemics; a knowledge which, indeed, promises to throw much light on the mode of propagation of many diseases which have been present here for centuries. The instances in which minute quantities of the ejections and dejections of cholera patients must be swallowed are sufficiently numerous to account for the spread of the disease; and on examination it is found to spread most where the facilities for this mode of communication are greatest. Nothing has been found to favour the extension of cholera more than want of personal cleanliness, whether arising from habit or scarcity of water, although the circumstance till lately remained unexplained. The bed linen nearly always becomes wetted by the cholera evacuations, and as these are devoid of the usual colour and odour, the hands of persons waiting on the patient become soiled without their knowing it; and unless these persons are scrupulously cleanly in their habits, and wash their hands before taking food, they must accidentally swallow some of the excretion, and leave some on the food they handle or prepare, which has to be eaten by the rest of the family, who, amongst the working classes, often have to take their meals in the sick room: hence the thousands of instances in which, amongst this class of the population, a case of cholera in one member of the family is followed by other cases; whilst medical men and others, who merely visit the patients, generally escape. The _post mortem_ inspection of the bodies of cholera patients has hardly ever been followed by the disease that I am aware, this being a duty that is necessarily followed by careful washing of the hands; and it is not the habit of medical men to be taking food on such an occasion. On the other hand, the duties performed about the body, such as laying it out, when done by women of the working class, who make the occasion one of eating and drinking, are often followed by an attack of cholera; and persons who merely attend the funeral, and have no connexion with the body, frequently contract the disease, in consequence, apparently, of partaking of food which has been prepared or handled by those having duties about the cholera patient, or his linen and bedding.