CHEMICAL EQUILIBRIA 135 



5 cc. of different blood-sera are given here. The 

 quantity of the precipitate was with : 



Human blood . . . . . 0-31 cc. 



Blood from gorilla . . . . o- 2 1 cc. 



,, ,, orang-utang . . . 0-13 cc. 



„ „ dog ape . . . . 009 cc. 



Blood from half- apes (lemurides) gave no pre- 

 cipitate. These animals have very little relation- 

 ship with man. In the same manner the whales 

 {cetaceans) were shown to be in relation with the 

 hoofed animals (ungulata) and the reptiles with the 

 birds. About 16,000 measurements were carried out. 

 In a similar manner the plants have been examined, 

 especially by Friedenthal and Magnus. Their 

 experiments indicated, for instance, a relationship 

 between yeast and truffle. 



Hamburger has made some quantitative measure- 

 ments of the quantity of precipitate formed by cen- 

 trifuging it in a tube which ended in a very narrow 

 graduated tube — 1 degree of the scale corresponded 

 to 0-4 cubic millimetres. These measurements were 

 given me for calculation. 



The simplest case was found with sheep serum 

 and the precipitin obtained by its injection in the 

 veins of a rabbit. Of the rabbit's serum containing 

 the precipitin always 04 cc. were mixed with a 

 variable quantity (A cc.) of the sheep serum diluted 

 in the proportion 1:49 with 09 per cent salt solution. 

 The quantity of precipitate P was measured (in 

 the unit 00004 cc). At the side of the observed 

 quantities I have written calculated values obtained 

 from the formula 



