446 PROTEIN POISONS 



when it comes from the shell, and yet the bacillus grows 

 luxuriantly in the extravascular blood of the chick. Hankin 1 

 was one of the first to show that other cells, besides the 

 leukocytes, contain germicidal substances. He made several 

 contributions to the study of so-called "defensive proteins/' 

 which he believed to be globulins. This is interesting in 

 view of the fact that ferments are often carried down with 

 globulins on precipitation with neutral salts. Bitter 2 was 

 unable to confirm Hankin's work, but it is needless to go 

 into this because we now know that many cells elaborate 

 germicidal substances. Christmas 3 prepared a germicidal 

 substance from the spleen and other organs by the following 

 method: The animal was killed with ether, opened under 

 aseptic precautions, the organ removed, cut into fine pieces, 

 covered with 50 c.c. of glycerin, and allowed to stand for 

 twenty-four hours and then filtered. The filtrate is treated 

 with five times its volume of alcohol and the precipitate 

 is immediately collected and washed with absolute alcohol. 

 Traces of alcohol are removed, so far as possible, by pressure, 

 and the precipitate is dissolved in 25 c.c of distilled water, 

 and air is blown through the solution to destroy last traces 

 of alcohol; then the fluid is filtered and its germicidal 

 action tested. Bitter 4 strove hard to find fault with this 

 agent and its method of preparation. He found it a power- 

 ful germicide, but he could not reconcile the fact that the 

 preparation of Christmas still proved a powerful germicide 

 after it had been heated to 65, while blood-serum loses its 

 germicidal effect when heated to 55. Buchner 5 had the 

 following to say on this point: "A method given by Christ- 

 mas for the preparation of germicidal solutions from the 

 organs of normal rabbits has also been tested by Bitter. 

 Germicidal solutions were indeed obtained, which, however, 

 differed materially from active serum, for in three experi- 

 ments, notwithstanding heating to 65, the germicidal 



1 Centralbl. f. Bakt., 1891, ix, 336. 



2 Zeitsch. f. Hygiene, ls>2, xii, 328. 



3 Annalcs de 1'Institut Pasteur, ls<)l, v, 487. 



4 Loc. cit. 5 Archiv f. Hygiene, 1893, xvii, 112. 



