H. B. HuTCHiNsox AND J. Claytox 16.") 



temperature for cellulose decomposition, and (2) the thermal deathpoiiit 

 of the organism. 



In pursuance of the first of these objects six portions of 2 grams each 

 of pure cellulose fibre were placed in flat bottomed cultivation vessels 

 and to each was added 100 c.c. of mineral salt solution with 0-2o per 

 cent, sodium nitrate, the solution having been rendered slightl_y alkaline 

 to phenolphthalein. The flasks were then inoculated with 1 c.c. of a 

 culture of the organism and incubated at 20°, 25° and 30° for 14 days. 

 At the end of this j)eriod the resulting cultures were acidified slightly, 

 filtered, and the residues dried and weighed. The losses of cellulose at 

 the different temperatures were found to be as follows: 



20° («) Cellulose decomposed 0-334 grm. 



20° (6) „ „ 0-302 grm., mean 0-318 grm. 



25° (a) „ „ 0-370 grm. 



25° (6) „ „ 0-414 grm., mean 0-393 grm. 



30° (a) „ ■ „ 0-414 grm. 



30° (6) ,, „ 0-446 grm., mean 0-430 grm. 



The most vigorous decomposition thus took place in the region of 

 30°. Owing to limited incubator capacity at that time it was not possible 

 to carry out a more extensive series, but subsequent experience has 

 shown that although decomposition does proceed at 35°, this is not so 

 rapid as at 30°. Moreover, the organisms exhibit certain abnormal 

 features and have also been found to display a marked reluctance to 

 grow in high dilutions at the higher- temperature. 



The determination of the thermal deathpoint has been carried out 

 on a number of occasions, and the results of two series are given. 



Series I. Length of Exposure — 5 minutes. 



Growtli after 48° 50° 52° 56° 58° 60° 62° 62-5° 66° 



days ++ ++ ++ ++ ++ + 



1 5 da^ys ++ ++ ++ ++ ++ ++ ++ ,- - 



Series II. Length of Exposure — 10 minutes. 



Growth after 40° 42° 44° 46° 48° 50° 52° 54° 56° 58° 60° 62° 

 7 days + 



9 days + 



In the two series the organism succumbed after exposure to a 

 temperature of 62° for 5 minutes or a temperature of 58° for 10 minutes. 

 In its thermal deathpoint S. cijtophaga thus resembles the majority of 

 the non-sporogenous organisms, as compared with the sporogenous 



