INFANT MORTALITY AND THE ENVIRONMENT. 225 



average temperature is less ; and, in general, that the number of 

 deaths from these causes is directly proportional to the elevation 

 of temperature, especially if it be long continued. Thus, of 3,216 

 deaths from the diarrhceal diseases in Vermont, New Hampshire, 

 Massachusetts, Rhode Island, and Connecticut in 1883, 2,745, or 

 eighty-five per cent, occurred during the months of July, August, 

 and September. The same States showed an increased mortality 

 from these causes during the unusually hot summers of 1880 and 

 1882. In the city of Boston, for the nine years from 1867 to 1875 

 inclusive, the mean temperature of the months of July and Au- 

 gust varied from 68*6° in 1874 to 72*3° in 1870, and averaged 70'5°. 

 The highest death-rate was in 1872, when the mean for the two 

 months was 71"9°, and for the hottest single month was 73'1° ; and 

 the lowest was in 1867, with a mean for the two months of 69*8°, 

 and for the hottest month of 70'4°. In New York, during the 

 month of July, 1872, the mean temperature was 79*57°, or 3'43° 

 higher than the average for the ten previous years. As a result, 

 the mortality for the quarter was the highest ever known in the 

 city, and that notwithstanding that the other two months were 

 not unusually hot. 



It must be stated that, fatal as is the effect of heat upon chil- 

 dren under five, the proportionate mortality is still greater when 

 the investigation is limited to infants under one year of age. Dr. 

 Blackader says that a very hot summer month will triple or even 

 quadruple the mortality of infants under one year, though that of 

 children from one to five is barely doubled. During the year 1872, 

 in New York, nearly sixty per cent of all deaths were under one 

 year of age, and more than forty per cent took place in the sum- 

 mer quarter. 



The effects of improper feeding are seen in the fact that, 

 whether in city or country, in hot summers or cool, only a very 

 small proportion of deaths from infantile diarrhoea occur among 

 infants who are. properly nursed upon the milk of a healthy 

 mother — which must be considered the only natural and proper 

 method of feeding young infants. 



Sir Hans Sloane showed years ago that the mortality of those 

 properly nursed upon breast-milk was to that of those who were 

 bottle-fed as 19'2 to 53"9 per cent. Dr. J. Wilmarth reports that 

 in a country practice in Massachusetts, out of one hundred and 

 one children nursed wholly, or nursed and fed with nursing after 

 a few months to weaning-time, and who were under his observa- 

 tion for a series of years, there were twelve deaths from various 

 causes, none of them from cholera infantum ; while among nine- 

 teen children artificially fed, there were during the same time 

 eight deaths, six of them from cholera infantum. Says Messener : 

 "Cholera infantum attacks only those children who have been. 



VOL. XXXIT. — 15 



