222 THE POPULAR SCIENCE MONTHLY. 



indefinitely — challenge our earnest attention and demand our 

 careful consideration. Let us first inquire what are the diseases 

 which are the immediate cause of the great bulk of infant mor- 

 tality. These may be grouped in four main classes, namely : 



(1) Tlie acute iiifectious zymotics, of which the chief are 

 measles, scarlet fever, small-pox, diphtheria, and whooping-cough. 

 These are collectively responsible for from fifteen to twenty per 

 cent of the deaths under five. 



(2) The acute lung-diseases, chiefly bronchitis and pneumonia, 

 which together cause from ten to fifteen per cent of the deaths 

 under five. In America, more than twice as many deaths occur 

 from pneumonia as from bronchitis, while in England nearly the 

 reverse is true. 



(3) Tubercular and constitutional diseases, such as consump- 

 tion, scrofula, meningitis, and hydrocephalus, which are responsi- 

 ble for from ten to fifteen per cent of the entire infant mortality. 



(4) The diarrhc^al diseases, comprising infantile diarrhoea, 

 cholera infantum, inflammation of the bowels, dysentery, and 

 some others. These are the cause of at least one fourth of the 

 entire infant mortality the world over ; while in America cholera 

 infantum alone is responsible for nearly or quite one fifth. 



But the problem before us is not one which can be solved by a 

 simple rehearsal of the names of diseases and the number of their 

 victims. These only show the form and manner of death, while 

 the ultimate causes lie far in the background. 



The real questions at issue relate to those influences which are 

 at work upon so large a proportion of infants and young children 

 the world over, tending to break down in them the power of resist- 

 ing disease, lessen their chances of a vigorous, healthy life, and 

 render them unduly liable to go down to early graves. What is 

 the nature of these influences ? What circumstances tend to in- 

 crease their activity ? Under what conditions and to what extent 

 may they be rendered inert, or their usual dire effects be avoided ? 

 By what means may an unfavorable environment be changed to 

 a favorable one, and the vitality and longevity of the race be 

 thereby increased ? 



In considering these questions, it must be remembered that the 

 causes of infant mortality are also the causes of adult mortality, 

 only in a less degree ; and that the health of a delicate infant is the 

 most sensitive measure which we possess of those influences which 

 are deleterious to health, either in infancy or adult life. 



The first of these deleterious influences in the order of time, 

 and unquestionably also of importance, is heredity. A very large 

 proportion of all children born into the world are either weaklings 

 or invalids from the beginning. They are born wrong. They come 

 from poor stock. The influences which determine their weakness 



