There are, nevertheless, many facts on record which, unless duly weighed, appear to lend a good deal of support to the theory of the contagiousness of typhoid fever. Among the most important of these are (1) the occurrence in rapid succession of several cases in the same house, and (2) the limited epidemics which occasionally follow the arrival of an infected person into a previously healthy locality. These facts are, however, susceptible of an entirely different explanation. 1. In those instances in which several cases of the disease have occurred in the same house, it not infrequently happens that some defect in its sanitary conditions is detected, or that the drinking-water is found to be impure. The same cause which produced the first case may, therefore, also have produced those which succeeded it. Indeed, the interval between the cases is sometimes so short that for this reason alone, if there were no other, they could scarcely be attributed to contagion. It not infrequently happens that the seizure of one member of a large family is followed on the next day by that of another, and on the third or fourth by that of still another. Now, while it is undoubtedly true that the period of incubation has appeared in some cases to be very short, we know that under ordinary circumstances it is usually about two weeks. 2. The explanation of the second fact is not more difficult, but in order that it may be clear to the reader it will be well to give in detail a few {249} of the instances on record in which the arrival of an individual sick with typhoid fever in a previously healthy locality has been followed by an outbreak of the disease. Nathan Smith refers to two cases of this character. In both of these the disease appeared to be communicated to several individuals by patients who had contracted the disease elsewhere. So little is said in the reports of these cases of the water-supply of the localities in which they occurred, or of the manner of disposing of the discharges of the patients, that they would scarcely now be used as arguments in favor of the contagiousness of the disease. The report of a local epidemic by Austin Flint, Sr., is more satisfactory in this respect, and is as follows: A stranger was detained in a small village near Buffalo by an illness which proved fatal in the course of a few days, and which was recognized as typhoid fever by his attending physicians. Up to this time, it is stated, typhoid fever had never been known in the neighborhood. In the course of a month more than one-half of the population, numbering forty-three, was attacked by the disease, and ten had died. The family of the tavern-keeper at whose house the stranger lodged was the first to suffer, and of the families immediately surrounding the tavern but one wholly escaped, that of a man named Stearns. Upon investigation, it was ascertained that this family alone, of all these families, did not use the well belonging to