Resorption of albuminoid fluids 107 



studied by several observers, who have made use of it for the recogni- 

 tion of human blood in medico-legal investigations 1 . 



Bordet 2 has made the discovery that intraperitoneal injections of 

 the milk of cows into rabbits provokes in the blood serum of the 

 latter the property of giving a specific precipitate with cow's milk 

 only. This precipitation bears a great resemblance to the coagulation 

 of casein ; which, however, does not justify us in identifying the 

 precipitating substance with rennet. This fact has been confirmed for 

 several other species of milk, and Schiitze 3 , in an investigation carried 

 on in the Berlin Institute, essayed to apply it to the differentiation 

 of the various kinds of milk. In the same order of ideas, researches 

 have been made on the artificial precipitins that develop in the blood 

 as the result of injection of white of egg and other albuminoids 4 . 

 Leclainche and Valle'e 5 have prepared animals in such a fashion that 

 their serum produces a precipitate with urinary albumen. The bio- 

 logical precipitin reactions are more sensitive than any of the chemical 

 reagents properly so called. These specific substances in the serums 

 must be looked upon as belonging to the group of soluble ferments, 

 approximating to the fixatives rather than to the cytases, since 

 they are unaltered by being heated to 56 C. Their action gradually 

 declines after passing 60 C. but is only destroyed at a temperature 

 beyond 70 C. 



An analogous soluble ferment has been discovered in the blood 

 serum of animals treated with injections of gelatine. We owe to 

 Delezenne, who has studied this question in his laboratory at the 

 Pasteur Institute, the most important and most complete data on the 

 resorption of gelatine. The blood serum of normal animals possesses 

 only a very feeble power, sometimes even none, of liquefying gelatine. 

 When however this substance is injected several times, the serum, as 

 is the rule for the formed elements and quite a series of fluid sub- 

 stances, acquires a much more pronounced activity. The gelatine, [us] 

 without giving any precipitate, is simply dissolved and will no longer 



1 Deutsch, Oompt. rend. XIII congres internal, de Med. de Paris, and Centralbl. 

 f. Bacteriol. u. Parasitenk., I te Abt., Jena, 1901, t. xxix, S. 661 ; Uhlenhuth, Deutsche 

 med. Wchnschr., Leipzig, 1901, S. 82 ; Wassermann u. Schiitze, Berl. klin. Wchnschr., 

 1901, S. 187; [Nuttall and Dinkelspiel, Journ. of Hyg., Cambridge, 1901, Vol. I, 

 p. 367 ; Nuttall, Brit. Med. Journ., London, 1902, I, p. 825]. 



2 Ann. de rinst. Pasteur, Paris, 1899, t. xin, p. 240. 



3 Ztschr.f. Hyg., Leipzig, 1901, Bd. xxxvi, S. 5. 



4 [Myers, Lancet, London, 1900, n, p. 98, and Centralbl. f. Bakteriol. u. 

 Parasitenk., I te Abt, Jena, 1900, Bd. xxvm, S. 237.] 



5 Compt. rend. Soc. de biol., Paris, 1901, p. 51. 



