470 CITY MILK SUPPLY 



rate fell to 101 in 1912 and to 84 in 1913 with indications that it would 

 drop to between 70 and 75 in 1914. Flies, of course, are one means of 

 spreading the stools of babies about. 



No one who has done tenement house inspection and seen the overfull 

 privies in the back yards and the unscreened windows and has observed 

 milk with a lot of struggling drowning flies in it standing in the hot 

 kitchens and has watched the flies swarming over the nursing bottles 

 has a particle of doubt but that in such habitations food, flies and feces 

 get badly mixed. 



Other phases of the problem of infant mortality have been brought 

 out by Schereschewsky in his paper on "Heat and Infant Mortality." 

 In showing the relation of temperature to infant deaths it has been cus- 

 tomary to compare the mean temperatures for weekly or monthly periods 

 with the infant deaths in like periods but Liefman and Lindeman in a 

 study of the infant mortality of Berlin, Germany, and also others have 

 shown that to study the direct effect of heat upon infant mortality the 

 daily temperatures and daily deaths must be compared. By using curves 

 constructed on this basis these two authors have demonstrated a well- 

 marked parallelism in the temperature and mortality curves and have 

 noted two well-marked peaks in the mortality curve. These indicate 

 excessive mortality in early summer and in late summer. 



The early summer mortality appears with the first atmospheric 

 temperatures above 73.4 and recedes shortly with the advent of cooler 

 weather. In cool years this early summer mortality may be lacking. 

 In this mortality many deaths occur after an illness of 1 to 2 days and the 

 deaths occur from causes mainly referable to affections of the central 

 nervous system. 



The late summer mortality extends from the middle or end of July 

 to the first of September, but in cool summers may be absent. It does 

 not recede with the first cool weather but is well-sustained and does not 

 drop markedly till the close of the year. It seems to express the sum- 

 mation of the effects of a long heated period plus irregularities caused by 

 sudden increases in temperature. As summer progresses the number 

 of deaths from gastro-intestinal diseases increases till by the end of 

 August 70 per cent, of the death certificates give diseases of this class 

 as the cause of death. Hot days increase the number of acute cases 

 but these dwindle in late summer. The fact that the late summer mor- 

 tality curve does not drop with the advent of cooler weather would seem 

 to suggest other causes of illness than high temperature but such is not 

 the fact. It is because the temperatures indoors do not drop with the 

 outside air temperatures that the death curve is maintained. 



Observations both in Europe and this country show that the indoor 

 temperature is often higher than outside temperatures. The slow diffu- 

 sion of heat through the walls is in large measure responsible for this. 



