BY R. GREIG SMITH. 607 



Before proceeding to describe the separation of the acids from 

 the ethereal extracts a few notes may be made upon the organic 

 acids mentioned in the table. The distillate from the mother 

 liquor had a strong odour of acetic acid and was neutralised with 

 soda. To a portion of the neutral solution silver nitrate was 

 added, whereupon a pasty, white precipitate was thrown down. 

 This was filtered, washed and dried on a porous tile, then in 

 vacuo over sulphuric acid and finally in the oven at 80° until 

 there was a loss of only 5 mgrm. in 30 minutes. A portion was 

 dissolved in water and the silver estimated as chloride in the 

 usual manner. 



0-3645 grm. gave 0-3115 grm. AgCl = 64-33 % Ag. 

 Silver acetate contains 64-68 % Ag. 



It is evident from the analysis of the silver salt that the acid 

 is acetic. 



The filtrate from the silver acetate rapidly darkened, which 

 made it appear probable that formic acid was also present. 

 Accordingly the neutralised distillate was tested and was found 

 to reduce alkaline permanganate to the brown hydrated binoxide 

 and also to produce a copious precipitate of calomel when treated 

 with excess of mercuric chloride. The latter test is characteristic 

 of formic acid. 



From the calcium sulphate residues a few droplets of an 

 insoluble fatty acid were obtained. The melting point was 

 determined by a method which I devised some ten years ago. 

 Two small particles of the dry solid acid are placed near one 

 another on a coverglass, another coverglass is put on the top and 

 very lightly pressed. The space between the particles after the 

 second coverglass is in place should be from one to two millimetres. 

 The preparation is then floated oh mercury and covered with a 

 small watch glass. The bulb of a delicate thermometer is inserted 

 in the mercury and the temperature slowly raised. At the 

 melting point the two particles of melting fat run together, the 

 space between them disappears, and almost instantly the molten 

 fat spreads out between the coverglasses. The melting point of 



