THE PHENOMENA OF INFECTION 447 



action remained." We have gone into this detail concerning 

 the preparation of Christmas for the following reasons: 

 (1) It remains to day a good method of preparing a germi- 

 cidal agent from the spleen or other tissue. (2) Its method 

 of preparation indicates that it is a ferment. (3) It is an 

 illustration of the fact that the degree of heat borne by a 

 ferment, without being inactivated, is dependent in part at 

 least on the character of the solvent in which the ferment 

 is found. 



Emmerich and his students 1 made the .following experi- 

 ments: A serum was dialyzed against distilled water until 

 its globulin was precipitated. The globulin-free serum 

 was precipitated with alcohol, and the serum albumin 

 thus thrown down was dissolved in 0.05 per cent, solution 

 of potassium hydroxide. This solution was found to be 

 markedly germicidal, and the conclusion reached was that 

 the germicidal constitutent of blood serum was an alkaline 

 albuminate. 



Vaughan and his students 2 published their first paper 

 upon the germicidal properties of nuclein. In their first 

 contribution they showed that nucleins prepared from 

 testes, thyroid gland, and yeast cells are markedly germi- 

 cidal to both pathogenic and non-pathogenic bacteria. 

 In 1894 Kossel 3 quite independently announced the dis- 

 covery of the germicidal action of nuclein and nucleic 

 acid. Vaughan not only demonstrated the germicidal 

 action of nuclein in vitro, but also showed (1) that it 

 protected rabbits against subsequent inoculation with 

 the pneumococcus; (2) it also protected a considerable 

 percentage of rabbits against inoculation with the bacillus 

 tuberculosis; (3) that it had a curative effect on rabbits 

 already inoculated with tuberculosis; and (4) that it 

 apparently benefited initial tuberculosis in man. 



It now turns out that the germicidal action attributed 

 by Vaughan and Kossel to nuclein was probably not due to 



1 Centralbl. f. Bakt., 1892, xii, 364. 



2 Medical News, May 20, 1893. 



3 Archiv f. Afcat. u. Physiol., Physiolog. Abtheilung, 1894, 194. 



