THE DESCENT OF MAN 67 



vestigations into the reaction of the blood have been 

 made by Friedenthal, Nuttal, Uhlenhuth, Wasser- 

 mann, Schiitze, and others, in some cases with the 

 express intention of tracing the relationship between 

 man and the higher apes, in others for various 

 purposes. Some years ago Dr. Friedenthal pub- 

 lished a work in which he declared, as the result of 

 his researches into the reaction of the blood, that 

 man was not only descended from apes, but was a 

 genuine ape himself. This conclusion is deduced 

 from the following facts. It is ascertained that if 

 the blood of one class of vertebrates, especially of 

 mammals, be injected into the veins of other 

 animals, symptoms of disease appear, in consequence 

 of the decomposition of the red corpuscles of one 

 kind of blood by the serum of the other. There is, 

 however, no such result when the two kinds of 

 animals are closely related. Careful experiments 

 have proved that there is a very feeble reaction 

 between human blood and that of apes, and this has 

 led to the inference that man and the anthropoid 

 apes must be closely connected. Conversely, in the 

 reaction of the antiserum, the morbid effect is most 

 marked in the case of animals most closely related. 

 Let us apply a critical standard to these experi- 

 ments and deductions. The experiments are 

 extremely ingenious, and are not only of great use in 

 forensic medicine, but they throw a very interesting 

 light upon the relationship existing between various 

 species. But we are not justified in regarding cc 



