HISTORIC 315 



as a means of identifying and differentiating certain species of bacteria, 

 but the test possesses no advantage for these purposes over agglutina- 

 tion reactions and is not generally employed. 



Tchistovitch was the first to call attention to the non-bacterial pre- 

 cipitins. This observer found that the serum of rabbits inoculated with 

 eel serum, when mixed with a small quantity of the eel serum, caused a 

 precipitate to form. 



About the same time (1899) Bordet found that the serum of rabbits 

 inoculated with the serum of chickens, when mixed with the chicken 

 serum, gave a specific precipitate. A little later Bordet produced an 

 anti-milk immune serum (lactoserum) by inoculating rabbits intraperi- 

 toneally with milk partially sterilized by heating to 65 C. When this 

 immune serum was mixed with the homologous milk, small particles 

 appeared, which gradually formed larger flak.es and sank to the bottom 

 of the fluid. It was found that the lactoserums were specific i. e., 

 cow lactoserum would precipitate only cow casein, human serum only 

 human casein, etc. 



Wladimiroff was the first to use the bacterial precipitin reaction as a 

 practical diagnostic test. He showed that the serum of a horse suffering 

 from glanders would, when added to a clear filtrate of a culture of Bacil- 

 lus mallei, produce a precipitate. The technic of these reactions is, 

 however, more difficult than with the agglutination tests, and as the 

 reactions are usually not more delicate or more advantageous than the 

 latter, they are seldom employed. 



Following Wladimiroff, Uhlenhuth and Wassermann made a very 

 important practical demonstration of the value of serum precipitins in 

 differentiating the blood and secretions of man and animals. For ex- 

 ample, the serum of rabbits immunized with various bloods would react 

 with solutions of old and dried specimens of their respective bloods, and 

 although " group" precipitins were found present in the tests with the 

 blood of closely allied species, yet the value of the reaction was not 

 impaired to any extent when a proper technic, with correct dilutions, was 

 employed. These discoveries were found to possess considerable value 

 in forensic medicine, particularly in the recognition of the source of 

 blood-stains. 



Nuttall, in a thorough and painstaking research with the blood from 

 500 animals, was able to study the "blood relationship" of various ani- 

 mals as based upon group precipitins. For example, the serum of a 

 rabbit immunized with human blood will react best with human serum, 

 then with the serums of the higher apes, and finally with the lower orders 



