56 The Glucoside Constitution of Proteid Matter. [June 8> 



It dissolves hydrated copper oxide in presence of excess of potash. 

 (Trommer's test), without producing a biuret reaction ; at least, 

 specimens are often procurable of which this can be said. 



With Fehling's solution, it gives a strong and neat reaction, the 

 reduced copper oxide falling as a dense red precipitate. 

 . Heated on the water-bath for two or three hours with pheriylhydr- 

 azine and acetic acid, it yields, on cooling, a crystalline osazone in the 

 form of needles clustered into sheaves or brushes, or radiating in 

 dense round masses. Often the composite character of these round 

 masses is only to be seen by close inspection of the circumference. 

 Whilst a certain type prevails, variations within limits are noticeable,, 

 and sometimes an approach to a spike constitution is observable. 

 The crystals are soluble in alcohol, from, which they may be recrystal- 

 lised. 



It gives with benzoyl chloride an insoluble compound, in accord 

 with the behaviour of carbohydrates. 



With a-naphthol and excess of strong sulphuric acid, it behaves 

 like sugar in giving a deep- violet colour, and leading on dilution to- 

 the formation of a violet-blue precipitate soluble in alcohol, ether, 

 and caustic potash, with the production of yellow solutions, but 

 insoluble in hydrochloric acid, a character by which, according to- 

 Molisch, the precipitate produced from sugar is distinguishable from 

 that derived from peptone and various albuminous bodies. 



With thymol and excess of strong sulphuric acid, it again behaves 

 like sugar, giving a deep-red coloration, followed, on dilution, by the 

 production of a carmine-red precipitate, soluble in alcohol, ether, and 

 caustic potash, with formation of pale-yellow solutions, and in am- 

 monia with formation of a bright-yellow solution. The precipitate, 

 as in the case of the a-naphthol test, is found to possess the character 

 of insolubility in hydrochloric acid. 



It is susceptible of being thrown down in combination with oxide 

 of lead, by the employment of lead acetate and ammonia, and is 

 afterwards recoverable from the compound. From the sugar thus 

 recovered, the usual reaction is obtainable with Fehling's solution 

 (provided the ammonia has been fully removed) ; and also the crys- 

 talline osazone with phenylhydraziue, of which micro-photographs are 

 furnished. 



From this assemblage of positive characters, it appears to me there 

 can be no doubt that the CuO reducing body obtainable from proteid 

 matter consists of sugar. I should state, however, that I have not 

 yet obtained it in a form to prove fermentable ; and Dr. Sheridan Lea, 

 who kindly examined it with the polarimeter, failed to notice any 

 rotation of which he could speak with certainty. He adds there was, 

 if anything, a tendency to lasvorotation, but not amounting to more 

 than 0-1. 



