1893.] The Glucoside Constitution of Proteid Matter. 55 



version into a CuO reducing material. For effecting this conversion 

 I have for years past been in the habit of using 2 per cent, sulphuric 

 acid. As I have said, my impression originally was that the product 

 consisted of glycogen, and from observations upon the conversion of 

 starch and glycogen into glucose, I had formed the opinion that 

 sulphuric acid of the strength named best met the requirements. 

 Boiling for about an hour and a half with an inverted condenser was 

 resorted to, or the autoclave was used, half-an-hour's exposure to a 

 temperature of 150 C. producing an equivalent effect, the results 

 given by the two methods being practically identical. Where the 

 object has been a quantitative analysis, the acid has been subse- 

 quently neutralised with potash, the sulphate formed not occasioning 

 any inconvenience ; but should it be desired to collect the reducing 

 product, the acid must be removed by precipitation, best effected by 

 the agency of barium carbonate ; the nitrate, after evaporation to 

 dryness on the water-bath, yields the material in the state desired. 



I had been led by certain circumstances to consider that the 

 reducing product derived from the action of the 2 per cent, acid did 

 not consist of glucose, and had unsuccessfully tried, by more extended 

 periods of boiling, to get it carried further. Subsequently I renewed 

 my efforts in this direction. In experimenting with cellulose, I had 

 found that but very slight action was produced by 2 per cent, acid, 

 while considerable effect followed the use of acid of 10 per cent, 

 strength, and it occurred to me that the body I was dealing with 

 might behave similarly. Trying 10 per cent, acid, I found that the 

 reducing power of the product became very nearly doubled, being 

 raised in the proportion of from between 50 and 60 to 100. I next 

 tried 50 per cent, acid, allowed to remain in contact with the product 

 for one to three days, then diluted to 20 per cent., and boiled. The 

 result stood about the same as after direct boiling with 10 per cent, 

 acid. After 15 per cent, acid, also, a like result was obtained. As 

 yet I have failed to carry the body to a higher stage of CuO reducing 

 power than that produced by 10 per cent, acid, but I am stilt led to 

 think that the glucose stage has not yet been reached. The effect of 

 raising the reducing power is to give a semblance of a corresponding 

 increase of material. 



The following are the characters of the product obtained after the 

 separation of the sulphuric acid by barium carbonate and evaporation 

 of the filtered liquid to dryness : 



It presents the appearance of a sugary extractive, and has a pro- 

 nounced baked-sugar odour. 



It is very soluble in water, only slightly so in absolute alcohol, but 

 considerably so in spirit of about 90 per cent, strength. 



It is readily diffusible. 



Boiled with caustic potash (Moore's test), the solution darkens. 



