CHEMICAL PHENOMENA IN LIFE 



obtained in albumoses and peptones, the most 

 primitive protein-bodies. There is every hope of 

 the possibility of soon explaining this reaction 

 much more exactly than is at present possible. 



But even now we see what complicated reactions 

 can take place among proteids, and how easily 

 precipitates are formed without seriously changing 

 the original proteids. Most remarkable is the fact 

 that the proteids of a species of plant or animal 

 do not give any precipitin reaction with the blood 

 serum of an animal treated with the proteid of the 

 same plant or the same animal. Therefore the 

 reaction can be used to distinguish whether a pro- 

 teid is an alien one, or one belonging to a certain 

 species. Experiments were made by Uhlenhuth 

 on anthropoid apes, and on groups of lower apes. 

 Anthropoid serum from animals which were 

 treated with the blood of man does not give any 

 precipitin reaction. But serum from other apes 

 which were treated with the blood of man gives a 

 distinct reaction. We see from this fact that the 

 blood of anthropoids is not essentially different 

 from that of man. The proteids are the same in 

 both. 



The result is that each species of organism 

 has its own specific proteids. We understand 

 now why the alien proteids which are taken in 

 with the food have to be split up until they finally 

 form amino-acids, so that the alien protein 

 structure is quite annihilated. Then the cells 



