is a most fatal disease among infants in the third quarter of each year. It is chiefly a disease of urban life, and occurs to a preponderant extent among the children of the artisan and still more of the unskilled labouring classes. It is much less abundant in towns which have adopted the water-carriage system of sewage than in those retaining the conservancy methods of removal of excrement (page [198]). Towns with the most perfect domestic and street scavenging arrangements have the least epidemic diarrhœa. An impervious soil favours a low diarrhœal mortality; while persons living on porous soils usually have much diarrhœa. I have shewn elsewhere that given two towns equally placed so far as social and sanitary conditions are concerned, their relative diarrhœal mortality is proportional to the height of the temperature and the deficiency of rainfall of each town, particularly the temperature and rainfall of the third quarter of each year. In other words there is a general inverse relationship between rainfall and diarrhœa and a direct relationship between temperature and diarrhœa. Thus wet and cool summers are adverse to diarrhœa. Ballard concluded that the summer rise of diarrhœal mortality does not commence until the mean temperature recorded by the 4-foot earth thermometer has attained somewhere about 56° F., no matter what may have been the temperature previously attained by the atmosphere. This is a convenient index, as the summer warmth does not immediately cause diarrhœa. All the above facts point to the conclusion that the fundamental condition favouring epidemic diarrhœa is an unclean soil, the particulate poison from which infects the air, and is swallowed most commonly with food, especially milk. Thus, diarrhœa, like enteric fever, is a “filth-disease.” As the contagium appears to gain entrance by food, the following card of precautions which is distributed each year in the poorer districts of Brighton may be reproduced here:
HOW TO PREVENT DIARRHŒA.
During the summer a large number of infants die from diarrhœa. Scarcely a single baby who was being suckled dies from this cause. It is evident, therefore, that in the prevention of this very fatal summer disease, precautions as to food are most important.
Attention to the following points would save many infants’ lives:—
1. Do not wean your infant during the hot months of July, August and September. To begin artificial feeding during hot weather is very dangerous.
2. If feeding by hand is absolutely necessary, carefully follow these directions:
(a) All milk should be boiled before being given to the infant.
(b) The infants’ food must be prepared fresh each time. (For particulars see below.) Milk and water, and still more “pap” or patent foods, if left two or three hours, “go bad,” and are then very highly dangerous to the infant.
(c) All jugs or other utensils used for storing milk must be scalded out and kept absolutely clean. They should be covered to prevent access of dust.
(d) The feeding bottle must be thoroughly scalded after each meal, and the tube thoroughly cleansed. It is best to use alternately two boat-shaped bottles without tubes. If the bottle smells sour, something is not clean, and the infant will suffer.