148 Decomposition of Cellulose 



plates which, under the microscope, appeared to consist wholly of the 

 filamentous organism, but inoculation to fresh medium and incubation 

 for a few days resulted, without exception, in the incidence of the coccus 

 form. 



Despite the preparation of a considerable number of subcultures 

 and the use of widely different media', we have been unable to effect a 

 permanent separation of these two forms, nor has the employment of 

 the media suggested by Kellerman and McBeth, whose paper appeared 

 about this time, been followed by any greater measure of success. 



Various attempts were made to set up conditions which might 

 conceivably favour one of the forms at the expense of the other. Experi- 

 ments were carried out, for example, in which tubes containing filter 

 paper and mineral salt.s were inoculated with a culture of the two forms 

 and then subjected to a range of temperatures varying by 2 from 40° 

 to 62°. After seven days, growth occurred in all tubes subjected to 

 temperatures of 40°-56° for ten minutes, while after nine days growth 

 was also evident in the tube heated to 58°. None of the tubes showed a 

 pure culture either of the thread or coccus form. 



Similarly, attempts to obtain simplification of the flora by differential 

 reaction of the media yielded negative results. Treatment of crude 

 cultures with volatile antiseptics was equally ineffective in bringing 

 about separation of the two forms. Chloroform, toluene, and carbon 

 bisulphide all had the effect of destroying both the filamentous and the 

 coccus forms. On the assumption that, on plating out, simple coherence 

 of the two forms occurred, mechanical dissemination of the cultures by 

 means of an atomiser and exposure of cellulose agar plates to the spray 

 was tried. In this manner we obtained characteristic colonies, but 

 none of these was found to be pure. \\'e were, therefore, inclined to 

 regard the mutual relationship of these two forms as strictly symbiotic 

 — neither of the forms being able to grow in the absence of the other. 

 It was obviously impossible under these conditions to ascertain which 

 of the forms was the one actually responsible for the observed changes 

 in the filter paper, and the investigation was, consequently, temporarily 

 abandoned. 



1 The media tested and found unsuitable for the growth of the cellulose decomposing 

 organisms, or which failed to allow of separation of the two forms, include nutrient gelatine 

 and nutrient agar with and without dextrose, sodium nitrate-mineral salt-cellulose agar, 

 sodium nitrate-dextrose agar, soil extract -cellulose agar, with the addition of I'O per cent, 

 of the following sources of nitrogen — asparagin, ammonium citrate, peptone, sodium am- 

 monium phosphate, potassium nitrate: Kellerman and JIcBetli's cellulose agar, dextrose 

 agar, starch agar, and the numerous solutions suggested by Meyer {loc. cil. p. 24) for 

 diagnostical purposes. 



