PRECIPITINS. 117 



is specific and these ovasera, which furnish such delicate reagents for 

 testing for egg albumin, do not give any precipitate with alkaline 

 albuminates, peptons, casein, or blood serum. However, it was 

 found that ovasera obtained from animals immunized to the albumin 

 of hen's eggs do react with the albumin of pigeon's eggs. Uhlenhuth 

 obtained feebly active ovasera by prolonged and excessive feeding of 

 rabbits with egg albumin by the mouth. However, the serum thus 

 obtained was only slightly active and it is probable that the small 

 amount of precipitin in this serum was due to traces of egg albumin 

 absorbed unchanged through the walls of the stomach or intestines. 

 Ovasera may be heated for one hour at 60° without injury to their 

 precipitins. 



Leclainche and Valine ' injected albuminous urine intravenously 

 into rabbits. They used in this way 20 c.c. at a time and repeated 

 at intervals until each animal received from 150 to 200 c.c. The 

 serum of animals thus treated furnishes a very delicate test for 

 albuminous urine, giving an immediate precipitation. Urinsera 

 do not precipitate non-albuminous urine. Moreover, if the ani- 

 mal has been rendered immune with a urine containing serum 

 globulin, the serum from this animal does not precipitate urine con- 

 taining serum albumin, and vice versa. Urinsera also precipitate 

 pleuritic and other exudates, thus showing that the proteids of al- 

 buminous urine and of these exudates are identical. There is some 

 contradiction in the statements concerning the action of urinsera on 

 the blood serum of man. This point needs more extended observa- 

 tion. Mertens ^ immunized a rabbit with placental blood serum and 

 found that the serum obtained from this animal produced a precipi- 

 tum in human blood serum and in albuminous urine from man, but 

 was without effect upon the blood serum of normal rabbits or upon 

 the albuminous urine of a rabbit whose kidneys had been injured by 

 the administration of cantharides. 



Zuelzer^ treated rabbits with from 5 to 10 c.c. of albuminous 

 urine (containing from 1 to 9 per m. of albumin) at intervals of from 

 one to three days for two weeks, obtaining from the animals thus 

 treated a serum which precipitated both albuminous urine and the 

 blood of man. 



Tchistovitch * rendered animals immune to eel serum which is 

 toxic, and obtained from the animals thus immunized a serum which 

 produced a precipitum in the eel serum. His conclusions are as 

 follows : 



1 . Eabbits, dogs, goats, and pigeons are easily immunized against 

 the serum of the eel ; it is infinitely more difficult to immunize 

 guinea-pigs. 



' Comples Rend/as de la SodSU de Hiologie, 1901. 

 'Deutsche med. Wbchenschrifi, 1901. 

 ' Deutsche med. Wochmschnft, 1901. 

 'Annales de Ulnstitut Pasteur, 13. 



