DEATHS PER 100000 period. The intensity and exceptional date of the wave of mortality which followed the epidemic are also well shown by the diagram opposite p. 722. This exhibits the death rate from typhoid fever in Springfield by months for the twelve years, 1881-92. The TYPHOID FEVER IN SPRINGFIELD. AVERAGE MONTHLY FOR 1892 ୮ 20 101 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MONTHLY MORTALITY (PER 100,000 INHABITANTS) FROM TYPHOID FEVER. marked improvement since 1883 and the enormous excess in August, 1892, at the height of the epidemic, are notable. It will be observed that the death rate from typhoid fever during this month was by far the highest during any month of the entire twelve-year period. Out of the whole number of cases one hundred and fifty, one hundred and one had milk sold by the same milkman (F. D. K.), while one hundred and thirty-five may have had access to the same milk. For aid in the preparation of the map, plates and diagrams we are indebted to Mr. R. D. Chase. 30 AN INVESTIGATION OF AN EPIDEMIC OF TYPHOID FEVER IN SOMERVILLE, DUE TO INFECTED MILK. BY WILLIAM T. SEDGWICK, Ph.D., BIOLOGIST OF THe Board. Towards the end of August, 1892, the attention of the Somerville Board of Health was drawn to a sudden and nearly simultaneous appearance of a number of cases of typhoid fever. The physicians reported the cases with commendable promptness, ten having been reported on August 23 alone, and an inquiry set on foot by the local Board of Health immediately revealed the fact that most, if not all, of the cases were served by one and the same milkman. Thereupon the Somerville Board reported the outbreak to the State Board of Health, and I was instructed to make an investigation. In view of recent experience in the Springfield epidemic, described in the previous paper, which I was still studying, I was able to work rapidly, and began by verifying the data already in hand. It afterwards appeared that during the three weeks, August 20 to September 10, there were in the entire city of Somerville thirtyfive cases of typhoid fever. Of these one was imported, one was plainly a secondary case, a third was a very old case tardily reported. Thirty-two cases were apparently primary and indigenous and remained to be accounted for. Thirty of these had been served with, or had had access to, milk supplied by one and the same milkman. Of the other two cases, one was an old case of which the diagnosis was uncertain, though there was also a possibility that it was itself secondary to an earlier one; the other was synchronous with the epidemic period, and was that of a young woman who was in the habit of buying milk at a certain bakery. A bakery next door to the one from which she was in the habit of buying milk was supplied with milk by this particular milkman, and the keeper of this bakery and her daughter were among the persons who suffered from typhoid fever. I could not get the young woman or her mother to admit that they had ever been in the nearer bakery which had the suspected milk; but as they had to pass it to get to their regular bakery, I cannot keep feeling that on some unusual occasion some member of the family had perhaps stepped into the nearer bakery and got some milk. This case coincided in time with the rest; but in view of the evidence I have considered it an unexplained case. The approximate location of the cases is shown upon the accompanying map. The usual theories of water infection, sewer emanations, etc., were advanced by some to account for the outbreak, but were all easily disproved. The city of Somerville uses the "Mystic" water supply of the city of Boston, and this supply is not altogether unobjectionable but, inasmuch as the same supply served the whole city as well as the neighboring cities of Charlestown and Chelsea, while the present outbreak was confined to a limited area, the theory of wholesale water infection was easily disposed of. The region most affected was a fine portion of the city with the houses in excellent sanitary condition. There was no reason to suppose that the air, water, ice or sewers were worse here than anywhere else. The only common bond of connection between the infected families which was not also shared by thousands of others who were uninfected was the milk supply; and even this was shared by a large number of families in one portion of the city in which no fever appeared. It became necessary, therefore, before adopting the theory of infection by contaminated milk to show not only (1) how the milk might have become contaminated, but also (2) how it happened that only one portion of the milkman's route was affected with typhoid fever, while another and important portion was not so affected. I addressed myself first to the problem of the infection of the milk, and after having interviewed the milkman at great length, for the sake of mastering the details of his business, visited the farms (in Littleton) from which the milk was said to have come. All of these proved to be free from typhoid fever, and to be examples of unusually decent dairies. From Littleton the milk was sent once a day to Somerville, arriving by train early in the forenoon at Union Square station the location of which is shown upon the map. I was further informed that from this point it was carried in a wagon, still in the cans used for shipment, holding eight and one-half quarts |