BY R. GREIG SMITH. 545 



hecating. In this respect it is similar to the arabin and metarabin 

 gums. Fehling's solution sometimes did and sometimes did not 

 precipitate the gum. These tests were made with the gum of 

 race i., after the slime had been heated in the autoclave and the 

 separated gum had been repeatedly precij^itated with alcohol to 

 remove the sugars. 



The bacterium also produces slime in fluid culture. A medium 

 containing saccharose 50, peptone 2, ammonium chloride 1, 

 potassium phosphate 1, magnesium sulphate 0*5, chalk 10, and 

 water 1000 grms. was, after sterilisation, infected and incubated 

 at the air temperature (25^). By the 10th day, the solution had 

 become very viscous, and from it a small quantity of slime was 

 obtained by treatment with alcohol. When made into an emul- 

 sion with water, the slime behaved to reagents like that grown 

 upon the surface of agar. 



The products of hydrolysis. — The slime from agar was purified 

 by repeated precipitation with alcohol from aqueous emulsion 

 until it was found to be free from sugars. The gum was then 

 obtained from the slime and its hydrolysis was attempted by 

 boiling with 5 % sulphuric acid. At the end of six hours a por- 

 tion was abstracted, neutralised and tested for reducing sugars. 

 Fehling's solution gave a pale blue flocculent precipitate, but 

 there was no reduction. At the end of twelve hours Fehlino-'s 



o 



solution gave the same negative reaction. The carbohydrate had 

 not been hydrolysed, and in this respect it is similar to pararabin, 

 which is not hydrolysed upon boiling with dilute sulphuric acid. 

 The sulphuric acid solution was divided into two and one of 

 the halves was evaporated to half volume ( = 10 % sulphuric acid) 

 and boiled for six hours. The other half was nearly neutralised 

 with baryta water, filtered and evaporated down with 50 c.c. of 

 normal phosphoric acid until the solution darkened in colour and 

 evolved the odour of burning sugar. The solution was then 

 diluted to 33 c.c. ( = 5 % solution) and boiled for six hours. 

 From the solution which had been boiled with 10 % sulphuric 

 acid, a few milligrams of an osazone which melted at 177-180^ 

 were obtained. The small quantity of osazone from the solution, 



