PLAXT AFFINITIES 227 



of resemblance must always be matter for sur- 

 prise to the plant lover whose attention is called 

 to it for the first time. 



That this intimate record of grades of cousin- 

 ship should be permanently fixed in the proto- 

 plasm of the plant itself is one of the most 

 mystifying and thought-compelling of biological 

 revelations. 



If anyone w r ere to doubt that the intimate 

 chemical structure of plant protoplasm and plant 

 juices may thus be depended on to reveal genetic 

 relationships, and to mark nice shades of distinc- 

 tion between allied forms, evidence from a quite 

 alien field might be cited that would set the 

 matter at rest. 



EVIDENCE FROM THE ANIMAL WORLD 



The evidence in question is furnished by an 

 extraordinary series of blood tests through which 

 Dr. G. H. F. Xuttall, the American Professor of 

 Biology at Cambridge University, has traced the 

 intimate relationship of large numbers of animals 

 of different orders. 



By inoculating rabbits with the blood of dif- 

 ferent species of birds, reptiles, and mammals, 

 Dr. Xuttall was able to develop an extraordi- 

 nary serum with which the intimate constitution 

 of the blood of other species of animals could be 



