ii SECONDARY DISSOCIATION-PRODUCTS 101 



much light on the existence of aromatic nuclei in albumins, long 

 before these aromatic bodies themselves had been isolated. 



Instead of studying the effect of impure cultures of so-called 

 'putrefactive bacteria,' pure cultures of definite bacteria were used 

 later on. Thus Nencki l and his pupils 2 examined the bacillus 

 of quarter-evil (Rauschbrand) under anaerobic conditions; Zoja 3 

 employed other anaerobes ; Kiihne 4 investigated the tubercle 

 bacillus ; Emmerling, 5 the Streptococcus longus; Taylor, 6 the 

 Bacterium coli and Proteus vulgaris ; Kutscher, 7 the'^y3&i?i$;5M''3rner, 8 

 the bacteria of the ' Gahrstromling,' a Scandinavian fooo!-stuff ? which 

 results from the action of apparently very definite ^icl-o-opgamisiii^ 

 on salt fish. These micro-organisms differ greatly from one another 

 in some respects, and therefore the results obtained by the above 

 researches have a high biological interest, but for the chemistry of 

 the albumin-molecule the investigations of Hoppe-Seyler, Baumann, 

 Ellinger, 9 and Spiro 10 are of greater importance, inasmuch as these 

 investigators did not subject the albumin as a whole, but only its 

 different primary dissociation-products, to the action of bacteria. 



Bacteria behave, in the first instance, exactly as do trypsin or 

 boiling acids, for they form at first albumoses and peptones, and 

 subsequently the amino-acids. The action of bacteria does not stop, 

 however, at this point, for Czapek n and Emmerling 12 have pointed 

 out that the a-amino-acids are the very best nutritive media for 

 bacteria. 



These amino-acids are acted upon by bacteria in two distinct 

 ways : 



(1) The amino-acids are converted into the corresponding simple 

 acids in exactly the same way as if they were acted upon with fixed 

 alkalies or with oxidising media. Owing to the elimination of 

 ammonia, there are formed : acetic, propionic, butyric, valerianic, 



1 M. Nencki, Monatshefte f. Chem. 1O. 506 (1889). 



2 M. Nencki and N. Sieber, ibid. 1O. 526 ; L. Nencki, ibid. 1O. 862 ; R. Kerry, 

 ibid. 10. 864 ; L. Selitrenny, ibid. 10. 908 (1889). 



:J S. Zoja, Zeitschr.f. physiol. Chem. 23. 236 (1897). 



4 W. Kiihne, Zeitschr.f. Biologic, 29. 1 (1892), 30. 221 (1894). 



5 0. Emmerling, er. d. deutsch. chem. Ges. 30. II. 1863 (1897). 



6 Al. E. Taylor, Zeitschr. f. physiol. Chem. 36. 487 (1902). 



7 F. Kutscher, ibid. 32. 419 (1900). 



8 C. T. Morner, ibid. 22. 514 (1896). 



9 A. Ellinger, Ber. d. deutsch. chem. Ges. 31. III. 3183 (1898) ; 32. III. 3542 

 (1899) ; Zeitschr. f. physiol. Chem. 29. 334 (1900) ; Ellinger and M. Gentzen, Hof- 

 meister's Beitrage, 4. 171 (1903). 



10 K. Spiro, ibid. 1. 347 (1901). 



11 F. Czapek, ibid. 1. 538 (1902), 2- 557 (1902), 3- 47 (1902). 



12 Emmerling, Ber. d. deutsch. chem. Ges. 35. II. 2289 (1902). 



