PRECIPITINS. 119 



in chickens' blood, also a^lutinized and dissolved the corpus- 

 cles. Uhlenhuth ' treated rabbits intraperitoneally with dilutions ot 

 chickens' blood, and obtained from the former animals a serum which 

 gave a precipitum with chickens' blood, but had no such action on 

 the blood of the horse, donkey, cow, sheep or pigeon ; nor did it 

 produce any precipitum in solutions of egg albumin, nor in the serum 

 of normal rabbits. 



Wolffs allowed chickens' blood to flow into four times its volume 

 of a one per cent, solution of salt and separated the corpuscles from 

 the plasma and injected both of these separately into two sets of 

 rabbits. From four to six injections at intervals of four to five days 

 were made and only those animals treated with the blood plasma 

 yielded a precipitum with chicken blood ; those treated with the cor- 

 puscles had no such effect. Other rabbits treated in the same man- 

 ner with dog's blood corpuscles and plasma gave similar results, the 

 precipitins being found only in those animals which had been treated 

 with the fluid portion of the blood. 



Uhlenhuth ^ treated rabbits intraperitoneally at intervals of from 

 six to eight days with 10 c.c. of defibrinated blood at each injection. 

 After the fifth injection the serum from the treated animals was ob- 

 tained and used for testing blood from various sources. The blood to 

 be tested was diluted with tap water until it was reduced to a feebly 

 red color (1 :100). This diluted blood was freed from stroma either by 

 filtration or by decantation, and two c.c. of it was placed in test-tubes 

 and diluted with an equal volume of double physiological salt solu- 

 tion (1.6 per cent.). It is important that blood should be diluted 

 with physiological salt solution and not wholly with water, which is 

 likely to cloud certain bloods when diluted. Blood thus prepared 

 was obtained from the ox, horse, donkey, pig, sheep, Aog, cai, deer, 

 hare, guinea-pig, rat, mouse, rabbit, chicken, goose, turkey, pigeon and 

 man. To tubes containing diluted blood from each of the above- 

 mentioned animals, from six to eight drops of the serum of the rab- 

 bit which had been treated with ox blood was added. The ox blood 

 was immediately clouded, while all others remained perfectly clear. 

 The clouding in the first mentioned grew in intensiiy and finally 

 formed floccules which gradually subsided. It will be seen that 

 by this test ox blood was easily distinguished from all others with 

 which it was compared. Uhlenhuth was also able to distinguish 

 ox blood from that of man or the horse, the three kinds having been 

 obtained from stains four weeks old. 



Stem * treated animals subcutaneously with human blood, employ- 

 ing from five to ten c.c. at each injection with intervals of two or 

 more days. After from two to three weeks, he obtained from the 



' Deutsche med. WocheTischrift, 1900. 

 'AnnaUs de PInsHtut Pasteur, 14. 

 ' DenUeche med. Wochengchr^, 1901. 

 * Deutsche med. Woehenschnfi, 1901. 



