256 MICROBES AND TOXINS 



it gives a result with an extract containing only y^^ny of 

 its weight of the protein to be determined. 



The precipitation test has given positive results with the 

 organs of forty-year-old mummies. It is even said to have 

 been successful with mummies of 3,000 to 5,000 years, but 

 in this case there is some doubt. It is probable that these 

 latter may contain albumoses, but probably they no longer 

 contain coagulable albumins. 



The same biological reaction has furnished an additional 

 proof of evolution. Just as there are group agglutinations, so 

 there are group precipitations. The antiserum which pre- 

 cipitates rabbit serum precipitates also hare serum. Anti-dog 

 serum precipitates with both dog and fox serum. The serum 

 against the horse precipitates also the serum of the ass and of 

 the tapir. The relationship, the blood relationship literally, 

 between the goat and the sheep, between the fowl and the 

 pigeon, and between the domestic and wild pig can thus be 

 demonstrated. 



What interests us more particularly is that the serum of a 

 rabbit prepared with human serum precipitates with the serum 

 of monkeys, a definite proof that we are their near relations. 

 This relationship extends even to the lemurs, which are only 

 half-monkeys, and is closer in the case of the monkeys of the 

 Old World than with those of America. Griinbaum, who 

 experimented with forty-six species of monkeys, maintains that 

 from the point of view of the quality and quantity of the 

 precipitates furnished by their sera, he has been able to detect 

 no difference between man, the gorilla, the orang-outang, and 

 the chimpanzee : this new proof of the correctness of man's 

 simian origin may be welcomed. 



Complement Fixation. 



This new sero-diagnostic took origin from an experiment of 

 Bordet : he was trying to show that there is in a serum, 

 not several, but a single complement and that it is the same 

 complement which acts in bacteriolysis as in haemolysis. 



