The Specific Precipitins 



121 



mann,* Morgenroth, and others, by whom it has been shown that 

 the reaction is sufficiently accurate to make possible the differentia- 

 tion of human and goat's milk. The most important practical 

 application of the specific character of the precipitins, however, 

 came through Uhlenhuthf and Wassermann,f who made use of it 

 for the differentiation of bloods for forensic purposes. 



Uhlenhuth gave rabbits intraperitoneal injections of 10 cc. of 

 defibrinated blood at intervals of from six to 

 eight days and found the blood-serum strongly 

 precipitant after the fifth. He used such serum 

 for testing the reaction with the bloods of oxen, 

 horses, donkeys, pigs, sheep, dogs, cats, deer, 

 hares, guinea-pigs, rats, mice, rabbits, chickens, 

 geese, turkeys, pigeons, and men. 



The method of making the test is important, 

 as carelessness of detail will interfere with the 

 accuracy of the result. The blood to be tested 

 is diluted about 1:100, or until it has a feeble red 

 color, with tap water, and then freed from cor- 

 puscular stroma by filtration or decantation. 

 Two cubic centimeters of it are placed in a 

 small test-tube, and further diluted with an 

 equal quantity of physiological salt solution (if 

 more water be added a precipitate of globulin 

 might take place and spoil the experiment). 

 To such a prepared blood solution, from six to 

 eight drops of the immune serum are added. 

 If the diluted blood come from the same kind of 

 animal as that whose blood was used to immunize 

 the animal furnishing the test serum, immediate 

 clouding takes place, and a flocculent precipi- 

 tate forms. The precipitate never occurs with 

 any other blood. 



Wassermann and Schutze prepared a test 

 serum by injecting rabbits with human blood, 

 precipitating powers upon twenty-three other kinds of blood and 

 found no precipitate except with the blood of a baboon, but the re- 

 action in that case was not nearly so marked as with human blood. 



The most interesting and one of the most important biological 

 applications of this phenomenon is by Nuttall, whose work, " Blood 

 Immunity and Blood Relationship" (Cambridge, 1904), should be 

 read by all who wish to study the subject for its scientific interest 

 as a means of determining the blood relationship of animals, or its 



* "Verhandl. d. Kong. f. innere Med.," 1900, 501, Wiesbaden. 

 f "Deutsche med. Woch.," 1900 and 1901. 



i"Samml. klin. Vortr. von Volkman," Leipzig, Verlag von Breitkopf and 

 Hartel, 1902. 



"Deutsche med. Wochenschrift," 1900, No. 30. 



Fig. 27. Poly- 

 ceptor (Ehrlich and 

 Marshall) such as 

 can be conceived to 

 occur in hemolysis 

 and bacteriolysis 

 where various com- 

 plements are en- 

 gaged, a, Receptor 

 of bacterial cell; b, 

 cytophil group of 

 the amboceptor; c, 

 dominating comple- 

 ment; d, subordinate 

 complement; a, /3, 

 c o m p 1 e m entophil 

 groups of the ambo- 

 ceptor, a for the 

 dominating, /3 for 

 the subordinate 

 complements. 



They tested its 



