H. B. Hutchinson and J. Clayton 



107 



of S. cylophciga in less than three to four days after inoculation, the 

 above loss of cellulose is by no means inconsiderable. 



A second experiment shows the relation between cellulose breakdown 

 and nitrogen supply. A number of flasks were prepared each with 

 2-0 grms. air-dry cotton wool and 100 c.c. of neutral nitrogen-free 

 mineral salt solution. After sterilisation, four of the flasks received a 

 sterile solution of sodium ammonium phosphate so that the concentra- 

 tion of the latter in the different culture flasks was equal to 0-5, 1-0, 2-0 

 and 4-0 grms. of the salt per litre of culture solution. After inoculation 

 and incubation for 21 days at 25° the culture in each flask was treated 

 with dilute (.3-3 per cent.) hydrochloric acid, boiled, filtered, and the 

 residue washed with distilled water and dried. The various data are 

 given in Table XII. 



Table XII. 

 The RehiioH of Nitrogen Supply to Cellulose Decomposition. 



The ratios for the three lower concentrations of nitrogen show good 

 agreement among themselves, the amount of cellulose destroyed being 

 about 30 times the quantity of nitrogen originally present. This con- 

 sistency may be taken as indicating that the whole of the nitrogen had 

 been utilised. With the most concentrated solution, the rapidity of the 

 action appears to have been checked ; it is also possible that the whole 

 of the nitrogen has not been completely utilised, but unfortunately an 

 actual determination of the residual nitrogen was not made. 



Bij-products of growth of S. cytophaga. Active cultures of S. cytophaga 

 have three main characteristics which may be stated to be (a) pigment 

 production, (b) the absence of obvious gas formation and (c) resolution 

 of the cellulose into a glistening mucilaginous mass. 



Pigment production. Growth of the organism on filter paper or 

 cotton wool, and especially when the reaction of the medium is slightly 

 alkaline, gives rise to the formation of a brilliant yellow pigment. It 

 may be extracted with ease from the liquid or dried cultures by means 

 of alcohol, the extract giving on concentration a dark yellow or orange 

 coloured oily residue. The pigment goes into solution with the ordinary 



