Literal Blood-relationship 93 



most instances, however, man can do little in the way 

 of inducing heritable variations; he has to wait for 

 what Nature supplies. 



Experiments on the transfusion of blood have an 

 interesting bearing on evolutionism. Friedenthal has 

 shown that there is harmonious mingling of the blood 

 of horse and ass, hare and rabbit, orang and gibbon, 

 chimpanzee and man. The harmonious mingling in- 

 dicates blood-relationship, near or distant. But when 

 the blood of an animal is transfused into a quite dif- 

 ferent type, there is great disturbance and, it may 

 be, much destruction of red blood corpuscles. It has 

 been shown by Uhlenhuth and Nuttall that if the 

 blood-serum of a rabbit which has had human blood 

 injected into it be added to human blood, a precipi- 

 tate is formed. When it is added to the blood of an 

 anthropoid ape, it forms almost as marked a pre- 

 cipitate, thus indicating a blood-relationship between 

 man and anthropoid. Let us follow the matter a step 

 farther, using a terse paragraph from Professor G. 

 Schwalbe's essay in Darwin and Modern Science, 

 edited by Professor Seward (Cambridge, 1909). 

 "The reaction to the blood of the lower Eastern 

 monkeys is weaker, that to the Western monkeys 

 weaker still; indeed, in this last case there is only a 

 slight clouding after a considerable time, and no 

 actual precipitate. The blood of the Lemuridae (so- 

 called 'half -monkeys') gives no reaction, or an ex- 

 tremely weak one, that of the other mammals none 

 whatever. We have in this not only a proof of the 

 literal blood-relationship between man and apes, but 



