4 HILDA HEMPL HELLER 



are actively saccharolytic and do split gelatin, for example the 

 Welch bacillus, vibrion septique, and many other fonns; these 

 organisms do not liquefy coagulated sermn or produce hydrogen 

 sulfide or other protein split products in any considerable quan- 

 tity. Most of them possess no diastatic power toward pento- 

 sans, and many fail even to split pentoses. The group next in 

 the scale are those anaerobes which, though they fail to disinte- 

 grate coagulated serum and muscle particles, are sufficiently 

 proteolytic to free considerable quantities of hydrogen sulfide 

 in media rich in sulfur, such as blood broth. The oedematiens 

 type, and other less well-known organisms may be placed here. 

 Some of these are strongly saccharolytic and others are weakly so. 

 Further advances in attack on the protein molecule are almost 

 invariably accompanied by a decrease in saccharolytic power. 

 B. aerofoetidus, and the two strains which I term Reglillus are 

 apparently slightly proteolytic, and only moderately saccharo- 

 lytic. The more highly proteolytic organisms usually split mono- 

 hexoses, glucose only, or no sugars at all. The most highly 

 adapted catalytic anaerobes are those that produce both acid and 

 aUcaU from their substratum in sufficient quantities to keep their 

 hydrogen-ion end point within their optimum range and which 

 are so highly proteolytic that they disintegrate a great variety 

 of protein molecules and split-products. Such t^-pes are B. 

 histohjticus and B. botulinus. Another type, known as Bifer- 

 mentans, keeps its end point within its optimum range of growth 

 but is not sufficiently proteolytic to continue multiplication for 

 a long period. Such organisms are not highly but widely special- 

 ized, and are adapted to fend for themselves because they are 

 saccharolytic as well as proteolytic. 



It is to render possible a future scientific and logical classifi- 

 cation of anaerobic organisms that this key and these generic 

 definitions are proposed. They are manifestly incomplete, 

 and it is certain that careful taxonomic investigations will require 

 the emendation of many of the proposed genera. But the 

 present paper aims to blaze a trail where meandering paths 

 have wandered — a trail upon which a highroad may be built in 

 the future. 



