62 EVOLUTION 



shown that there is great variability in the 

 character of the tail and bristles of Artemia 

 salina, and that the tailless form is connected 

 by intermediate stages with the fully tailed 

 typical form. A careful discussion of this 

 freguently misstated case will be found in 

 Bateson's "Materials for the Study of 

 Variation" (1894). 



Direct Evidence of Blood Relation- 

 ship. — Various workers — Friedenthal, Uhlen- 

 huth and Nuttall — have brought forward 

 experimental evidence of blood-relationship, 

 and this in the most complete and literal 

 sense. Friedenthal points out that when 

 the blood of a horse is transfused into an ass, 

 that of a hare into a rabbit, or that of an 

 orang into a gibbon, or that of man into a 

 chimpanzee, there is a harmonious mingling 

 of the two. But when human blood is 

 transfused into eel, pigeon, horse, dog, cat, 

 lemur or "non-anthropoid" ape, there is no 

 harmonious mingling. The human blood 

 serum behaves in a hostile way to the other 

 blood, causing great disturbance, marked, 

 for instance, by the destruction of the red 

 blood corpuscles. The difference in the two 

 sets of cases is that in the first the organisms 

 are closely related, in the second they are not. 



Another form of the same kind of experi- 

 ment is given by Uhlenhuth and Nuttall. 



