106 LEO F. RETTGER 



If there is any one related science which, to the bacteriologist, 

 is more important than any other, it is chemistry. It is indeed 

 unfortunate that there are few chemists who are also bacteri- 

 ologists. It is to be regretted also that comparatively few bac- 

 teriologists are familiar with the principles of chemistry. The 

 latter assertion is well borne out by the failure of systematists 

 to evolve even moderately successful classification schemes, 

 and by the action of committees on standard methods whose 

 choice of standard methods has not always been the 

 wisest. It required a Jensen to show the way to a newer and 

 morie rational system of bacterial classification; and it was not 

 until physical chemists came to our aid that a scientific and prac- 

 tical method of determining the H ion concientration of a culture 

 medium was supplied. The study of antiseptics and chemical 

 disinfectants has received a new impetus through the work of 

 Chick and Martin (1908) and the recent researches of Dakin 

 (1916) and his associates. 



Pasteur's victory over Liebig in their noted controversy on 

 the exact relationship of the yeast cell to fermentation was a 

 victory for the biologist. Buchner's researches on the enzymes 

 of yeast somewhat reversed the tables again, and today we are 

 more and more being led to believe that practically all trans- 

 formation of bacterial substrates is brought about through the 

 immediate agency of an enzyme, whatever that may be. 



Exhaustive chemical investigations into the composition of 

 bacteria and their multitudinous products are necessary before 

 we can acquire an understanding as to what bacteria in reality 

 are and what they can do. The investigations of Von Nencki 

 and his pupils promised a wide development of this field. Others 

 have made most valuable contributions, as for example Brieger, 

 Kiihne, and the Martins. In more recent times, the researches 

 of Tamura on the chemistry of bacteria, are of particular inter- 

 est; also the work of Armand-Delille (1913) and his associates 

 on the significance of amino acids and di-amines in culture 

 media, and the investigations of others (Sasaki, (1912) Otsuka 

 (1916), etc.) on the possible role of polypeptides in bacterial 

 nutrition. 



