THE EVOLUTION THEORY 139 



method was therefore adopted many years ago in forensic 

 medicine in Germany and most other civilized countries. As 

 it is further possible to detect in sausages the presence of 

 horse and dog flesh, biochemistry is a powerful adjunct in the 

 prevention of adulteration of this kind of food. 



Instead of blood other albumens may be used. Thus 

 Uhlenhut showed that the blood-serum of a rabbit which had 

 received at regular intervals in the abdominal cavity injections of 

 solutions of albumen from a fowl's egg caused a strong precipi- 

 tate if mixed with a solution of such albumen, but no precipitate 

 if mixed with a solution of any other albumen. Thus it is now 

 possible to distinguish between the albumen of the various 

 species of birds. These precipitates may still be distinctly 

 observed in dilutions of 1 gramme of albumen to 100 litres of 

 water. Ascoli states that he has observed reaction in dilutions of 

 1 in 1,000,000. An interesting fact in this connection is that von 

 Hansemann succeeded by the biochemical method in determin- 

 ing the origin of mummies more than five thousand years old. 



I have now completed my task of giving in large outlines 

 the facts that prove the gradual evolution of the organic world. 

 We have seen that palaeontology, comparative anatomy, the 

 history of evolution, and finally, the investigations of bio- 

 chemistry, all form a chain of evidence for the truth of the 

 Evolution Theory in which every link is firmly forged. 



