THE PHENOMENA OF INFECTION 445 



blood is the serum albumin. How much serum albumin 

 remains in blood serum after it has been thoroughly digested 

 with pepsin ? He could scarcely have chosen a more positive 

 method of demonstrating that the germicidal constituent 

 is not serum albumin. Either his pepsin was not active 

 and on this supposition his experiment was without value, 

 or the active constituent of the blood-serum is a substance 

 that is not destroyed or materially altered by peptic diges- 

 tion. We know that the peptones not only have no 

 germicidal properties, but that they belong to that class 

 of proteins that is most favorable to the growth of bacteria. 

 We recognize this fact when we add peptones to the various 

 artificial media on which we cultivate bacteria." We will 

 return to this point after proceeding farther with the 

 chronological order in which this research has developed. 



Prudden 1 found that ascitic and hydrocele fluids restrain 

 the development of certain bacteria. Rovighi 2 reported 

 that the germicidal action of the blood is increased in 

 febrile conditions. Pekelharing 3 enclosed anthrax spores in 

 bits of parchment and introduced these under the skin 

 of rabbits. Thus treated the spores soon lost their viru- 

 lence and finally their capability of growth. The destruc- 

 tion of these spores could not have been due to phagocytes 

 which did not penetrate the parchment, but must have 

 been caused by soluble substances. Behring and Xissen 4 

 found that the serum of the white rat, the dog, and the 

 rabbit destroy anthrax bacilli, while serum obtained from 

 the mouse, sheep, guinea-pig, chicken, pigeon, and frog 

 has no such action. It will be observed that in this there 

 is no constant relation between the germicidal action of 

 the blood of animals of different species and their suscep- 

 tibility to the infection. Thus the rabbit is highly suscep- 

 tible to anthrax notwithstanding the fact that its blood 

 destroys large numbers of this organism. On the other 

 hand the chicken is immune to anthrax from the moment 



1 Medical Record, 1890. 



2 Atti della Acoad. Med. di Roma, 1890. 



3 Ziegler's Beitrage, viii. 4 Zeitsch. f. Hygiene, 1890, viii, 412. 



