410 STENGEL — SPECIFIC PRECIPITINS. [Dec. 5, 



this direction have been made with fresh egg albumin. Taking 

 the white of fresh hen's eggs, we injected from lo to 15 c.c. 

 into the peritoneal cavity of rabbits. No striking effect resulted 

 from the injections, which were repeated at intervals of a day 

 or two until the rabbit had received from six to ten injections. 

 At the end of that time the serum of the animal was found to pre- 

 cipitate diluted solutions of egg albumin in a striking manner. The 

 same serum had no effect upon serum albumin and globulin con- 

 tained in the blood of man or various animals, but was not specially 

 tested regarding its behavior toward the albumin of other than 

 hen's eggs. Uhlenhuth, who has experimented in this manner, 

 found, however, that the precipitin is not specific, since the serum 

 obtained from animals immunized with hen's eggs reacts toward 

 pigeon's eggs. He found, however, as we did, that this serum did 

 not react with peptone, casein, blood serum, etc. 



Experiments similar to the above were made by Leclainche and 

 Vallee, who injected albuminous urine, and Ziilzer, whose work 

 was practically the same. Mertens and Tchistovitch used eels' 

 serum and placental blood serum respectively and found results 

 similar in character to those already detailed. 



The most interesting line of work, however, is that done by 

 Uhlenhuth and repeated or elaborated by Wolff, Stern, Wassermann 

 and Schlitze, Dieudonne, Nuttall, as well as by myself and Dr. C. 

 Y. White. These experiments concern themselves with the pro- 

 duction in the blood of specific precipitins for heterologous blood, 

 and these have been utilized to a certain extent in the determina- 

 tion of diseased conditions or more particularly for the differentia- 

 tion of human and animal blood. 



The manner of procedure in the preparation of the serum is as 

 follows : Rabbits (which have been found to be the most suitable 

 animals) are injected interperitoneally with blood serum or with 

 defibrinated blood About 10 c.c. is injected at intervals of from 

 two to three days until from five to eight or ten injections have 

 been given. The serum may be utilized immediately after the last 

 injection or the animal may be allowed to rest for a week before its 

 blood is drawn. The blood is then taken after killing the animal 

 or a small quantity may be obtained by bleeding after etherization 

 from one of the large blood vessels. The serum is collected after 

 separation of the clot. Fresh blood may be tested directly with 

 the serum by diluting the blood (i : 100) with isotonic salt solution. 



