448 PROTEIN POISONS 



this agent, but to ferments which came out with the nuclein 

 from the cells used in its preparation. This should have 

 been known at the time the work was done, because both 

 of these investigators were aware of the fact that a tempera- 

 ture short of boiling destroyed the germicidal properties 

 of their solutions, but we did not know so much about 

 cell ferments then as we do now. This, of course, does not 

 mean that all the results obtained with preparations of 

 nuclein, such as an increase in the number of leukocytes, 

 were due to the ferment contained in the preparations, 

 but it is more than probable that the germicidal action was 

 due to the ferment. The whole matter demands reinves- 

 tigation. 



It should be stated that Vaughan and McClintock 1 

 demonstrated the presence of nuclein in blood-serum. This 

 was done by precipitating a large amount of serum, obtained 

 under aseptic conditions, w y ith alcohol and digesting the 

 precipitate with artificial gastric juice so long as digestion 

 proceeded, the completion of digestion being indicated by 

 failure to respond to the biuret test. The small amount 

 of protein material which wholly resisted gastric digestion, 

 and which could be only nuclein, was dissolved in 0.12 

 per cent, potassium hydroxide, and its germicidal action 

 demonstrated on the bacillus of cholera, anthrax bacillus, 

 typhoid and colon bacilli, and on various cocci. At the 

 same time it was shown that a 0.5 per cent, solution of the 

 alkali was without effect upon these organisms. 



It then seemed that the whole question of the germicidal 

 action of the blood was practically settled. The leukocytes 

 contain large quantities of nuclein. The blood serum 

 contains small quantities of the same substance. That of 

 the serum comes from the leukocytes either in the form of 

 a secretion or as a result of the breaking-down of the cells, 

 and nuclein is a powerful germicide. The phagocytes 

 destroy bacteria either by engulfing and then digesting 

 them, or through the action of the nuclein dissolved in the 



1 Loc. cit. 



