1")<! Decomposition of Celhdose 



Relations to Sources of Nitrogen. 



Early attempts to obtain pure cultures of Spirochaeta cytophana by 

 means of the conventional media sufficed to demonstrate the unsuit- 

 ability of such media as nutrient agar and nutrient gelatine with and 

 without the addition of dextrose. The invariable result was that while 

 any organism resembling S. cytophaga failed to grow, various contami- 

 nating forms were secured which, on transference to cellulose' media, 

 were found to be incapable of bringing about any dissolution. The 

 absence of cellulose from these media might, of course, have contributed 

 materially to these negative results, but later experience indicated that 

 ack of growth was more probably attributable to (a) the concentration 

 of soluble compounds and (h) the uiisuitability of the more complex 

 nitrogen compounds as sources of nitrogen. 



.A^lthouiih the use of nutrient aj^ar had, therefore, to be abandoned, 

 various attempts have been made to induce growth of the organisms 

 on this medium, and in this respect the following may be mentioned. 

 Negative results were obtained when agar plate cultures were made 

 from dilutions of 1/200, 1/40,000 and 1/4,000,000 of active culture, the 

 organisms being evenly distributed in the usual manner. Equally bad 

 results followed the transference of loopfuls of active culture to the 

 surface of nutrient agar plates. When masses of decomposing filter 

 paper were transferred to the surface of nutrient agar plates, slow growth 

 of the organism or, at least, continued enzymic action was evident. 

 The paper was gradually resolved and gave rise to a semi-translucent 

 bacterial mass, yellow in colour and of mucilaginous consistency. The 

 bacterial filaments became highlv granular and apparently suffered in 

 vitality. Transference of portions of this bacterial mass to fresh nutrient 

 agar was not followed by growth, thus showing that the capacity of 

 growth without cellulose had not been acquired. 



The relations of the organism towards peptone have been investigated 

 and the results are given in Tables I and II. In the preliminary set 

 (Table I) a short range of concentrations was tested, in all of which growth 

 occurred with the exception of 1-0 per cent, solution. As it was possible 

 that this solution had not received its proper amount of inoculant, 

 several reinoculations were made with active culture from the next 

 lower concentration but these also failed to give rise to growth. There 

 was thus no acclimatisation to higher concentrations. 



The second series included a set of tubes without cellulose to test 

 the capacity of the organism for growth on peptone. 



