CHAPTER III. 



CAUSES AND SIGNS OF PHYSICAL DETERIORATION. 

 Modern Care for the Individual. 



IN the last chapter we saw that while selection is an 

 evident and powerful factor in the production of racial 

 change, there is but slight and in many cases ques- 

 tionable evidence that acquired characters are ever 

 transmitted. During their lifetime a man or woman 

 may be subject to the most varied conditions, and 

 yet the quality of his or her offspring will not be 

 affected by these conditions except in cases where im- 

 poverishment or poisoning of the blood has ensued, 

 thereby enfeebling his or her reproductive cells. These 

 facts have not been gained by a study of the lower 

 animals alone, for most researchers have kept man in 

 view, while others, like Malthus and Galton, have con- 

 fined their observations almost exclusively to the 

 human kind. In this chapter we shall see how these 

 generalisations are borne out by the study of disease, 

 and we shall see what effect the modern methods for 



the treatment of the sickly and feeble are having 

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