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TEXTBOOK OF ZOOLOGY 



been done through the application of medical science, together with 

 public health and other measures that have come with the development 

 of a humanitarian consciousness. Nothing but praise should be given 

 to an altruism that saves lives and relieves suffering, but the effect on 

 our race of man's present practice of preserving individuals that 

 Nature would have destroyed, without safeguarding the reproductive 

 advantage of the fitter group, is worthy of consideration. 



Fig. 438. — Family from Brazil showing- hereditary absence of hands and feet. 

 The man in the picture is the uncle of the children shown. The father, who is dead, 

 had the same deformity. Of the twelve children six were normal and six w^ere 

 deformed. (From Holmes, Human Genetics and Its Social Import, published by 

 McGraw-Hill Book Company.) 



It has been shown by Lorimer and Osborn* that certain large groups 

 are increasing so rapidly while others are so diminishing, that the 

 surviving children of a million women of reproductive age of the first 

 category will be twice as numerous as the surviving children of a 

 similar group of women of the second classification. Carried on at the 

 same rate for three generations (which is only a long lifetime) the 

 descendants of the first groups will be sixteen times as numerous as 

 those of the second groups. 



♦Lorimer, F., and Osborn, F. : Dynamics of Population, Macmillan. 



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