INFANT MORTALITY AND THE ENVIRONMENT. 223 



to-day have been at work for ages upon ages. That was no sar- 

 casm, but the plainest statement of scientific truth, on the part 

 of Oliver Wendell Holmes, when, after declaring his conviction 

 that every disease might be cured if taken in season, he added, 

 significantly, that in some cases it would be necessary to begin a 

 hundred years before the patient was born. This is a hard world, 

 and no weakling ever has half a chance. " The survival of the 

 fittest " is a merciful provision of nature. " The strongest live 

 and the weakest die." A race of criminals, paupers, and idiots 

 deteriorates with each successive generation, and goes down to 

 speedy extinction. It is the robust, sturdy, clear-headed, strong- 

 handed toiler of to-day, whose sons and daughters will inhabit 

 homes of wealth and occupy positions of responsibility a few 

 years hence. 



The effects of unfavorable heredity may be manifested in va- 

 rious ways. In the first place, the child may be born with the 

 disease already developed. Examples of this class may be seen in 

 hypertrophies, atrophies, and inflammations of various organs ; 

 in exudations, as hydrocephalus ; in infantile syphilis ; in new 

 growths, such as nsevus, tumors, and certain forms of cancer ; in 

 the pre-natal deposition of tubercles, parasites, and some inorganic 

 products ; in arrests of development, such as cleft-palate, hare-lip, 

 spina bifida, and that defective closure of the heart which pro- 

 duces cyanosis ; and in those unusual developments known as 

 monstrosities. Secondly, the disease may be transmitted, although 

 its manifestations are not developed at birth. This may be the 

 case with some of the diseases already mentioned as also occurring 

 in the first class, as well as with many others. Examples are seen 

 in scrofula, cancer, consumption, epilepsy, rheumatism, gout, in- 

 sanity, and the " specific " disease. Again, there may be no actual 

 disease, but only a tendency to disease, in the shape of an inherited 

 weakness of some special organ or in some particular direction. 

 These tendencies render their possessors unduly liable to suffer 

 from particular diseases, but do not make it necessary that they 

 should do so, provided that their environment is favorable. 

 Lastly, the faulty heredity may be manifest only in a general 

 weakness of the whole system, a lack of vigor and vitality, which 

 renders its possessor an easy victim to whatever malady may 

 attack him. This is the cause of many of the deaths which are 

 registered under the heads of infantile debility, diarrhoea, brain- 

 disease, and other common affections of infancy. 



To the actual diseases, special weaknesses, and unsound consti- 

 tutions resulting from unfavorable heredity, add now the envi- 

 ronment of poverty, with its usual accompaniments of ignorance, 

 carelessness, and inefficiency on the part of the parents, resulting 

 for both parents and children in privation of food, clothing, shel- 



