BY R. GREIG SMITH. 401 



a uniform swelling. It had an acid reaction to litmus paper. 

 By heating in the autoclave for ten minutes at 3-4 atmospheres a 

 slimy sediment (apparently gummy) and an almost clear, slightly % 

 acid, supernatant fluid was produced. The slimy sediment was 

 mixed with water treated with 2-3 drops dilute sulphuric acid 

 and again heated in the autoclave. This gave a curdy precipi- 

 tate and supernatant solution. The curdy precipitate was 

 apparently free from gum, and as it probably consisted of 

 coagulated bacteria it was not examined further. The faintly 

 acid solution from the first autocla\'e treatment was tested with 

 a few reagents. Lead acetate, barium hydrate and barium 

 chloride gave no precipitate. Basic lead acetate and ammoniacal 

 lead acetate gave precipitates. Fehling's solution gave no pre- 

 cipitate and no reduction on heating. Copper sulphate followed 

 by sodium hydrate gave a precipitate which coagulated on boiling 

 without change of colour. Alcohol gave an opalescent solution 

 which flocculated readily with potassium chloride. 



The gum acids in the mixed solutions from the autoclave treat- 

 ment were precipitated with alcohol and potassium chloride and 

 kept over-night in contact with the alcohol. The precipitate 

 was very contractile, and on treatment with water it partly 

 dissolved and partly swelled up, forming a practically unfiltrable 

 suspension. A portion of this was preserved; it had not dissolved 

 at the time of reading this paper, i.e., in one month; the gela- 

 tinous lumps were still evident. We have in this insolubility of 

 the gum acids a condition identical with what occurs on treating 

 the semi-insoluble wattle gums with water, and confirms the 

 deduction made from other observations that this bacterium is 

 responsible for the production of the metarabin of these gums. 

 The gelatinous lumps of gum acids were insoluble in dilute acid, 

 but readily dissolved in dilute sodium hydrate, from which dilute 

 hydrochloric acid precipitated the gum acids. 



The acids were dissolved in dilute sodium hydrate, neutralised 

 with sulphuric acid, and enough 5 % sulphuric acid was added to 

 make a 2 % solution. This was boiled under a reflux condenser 

 for two and a half hours. A white precijDitate which contained 



