1(32 Deconiposltiou of Cellulose 



of certain of the salts is very low, they tend to show only slight inhibitory 

 powers. 



Table VIII. 



Relative Effects of Organic Calcium Salts. 



From these experinaents the conclusion appears justified, therefore, 

 that representatives of the lower fatty acids, and of di- and tri-carboxylic 

 acids, are equally unsuitable as sources of carbon as are the carbohydrates, 

 since the organism completely failed to grow in any of the solutions in 

 the absence of cellulose. In regard to their inhibitory power, both 

 calcium formate and acetate are only slightly inimical in 0-1 per cent, 

 solutions and this also appears to be the case with malate, oxalate, 

 tartrate and citrate. This might at first be explained on the basis that 

 the maximum solubility of the latter compounds is lower than the 

 amount of the salt actually added, but this assumption makes it difficult 

 to account for the obvious inhibition in the 1-0 per cent, solutions. It 

 should be remembered, however, that the possibihty of a slight amount 

 of interaction with the constituents of the mineral salt solution and the 

 formation of more soluble alkaU salts is not entirely excluded. Both 

 calcium propionate and calcium butyrate show inhibitory effects in 

 0-1 and 1-0 per cent, solutions. 



The above work on the nutrition of the organism may be summarised 

 as follows. The nitrogen requirements of S. cytophacja may be fulfilled 

 by a range of nitrogen compounds — ammonium salts, nitrates, amides, 

 amino-acids and peptone — provided that these, and especially the 

 organic compounds, are not present in other than low concentrations. 

 With peptone this is particularly the case, the critical concentration 

 having been found to lie in the region of 0-25 per cent. Ammoniacal 

 and nitric nitrogen are, on the whole, markedly superior to the other 

 forms tested and may be supplied in much higher concentrations without 

 inhibitory effects being introduced. S. cytophafja appears to be specific 

 in its relation to carbon sources and its requirements are only met by 

 cellulose. Not only are other compounds — higher alcohols, organic acids 



