1881.] Physiology of Sugar in the Animal System. 



423. 



action in the aqueous extract noticeable before subjection to sulphuric 

 acid and heat, arose from the glucose not having been thoroughly 

 extracted in the alcoholic process, and the increased reducing action 

 after sulphuric acid and heat was due to the presence, in addition to 

 the glucose referred to, of a little Bernardin (glycogen) dissolved out 

 from the residue by the water. 



The plan that I adopt for effecting the complete removal of the 

 glucose is as follows : — The defibrinated blood which has been taken 

 for examination is poured into the requisite quantity of spirit, and the 

 two are well stirred together. I am under the impression that it is 

 advantageous for the coagulum to be allowed to remain in contact 

 with the spirit till the following day. After being boiled by the heat 

 of the water bath, the alcohol is strained off through a piece of linen 

 material which has been cleansed so as to be free from dressing. 

 Washing with alcohol is performed, and the coagulum in the linen 

 is subjected to forcible squeezing in a suitable sized press. The 

 residue, which by this process is converted into a dry cake, is pulverised 

 in a mortar, mixed with fresh spirit, boiled over the water-bath, and 

 again strained and pressed. The process is repeated once more, and 

 this I find is sufficient. Thus extracted three times, there is practically 

 no glucose left in the solid residue, and when an aqueous extract is 

 made it gives no appreciable cupric oxide reducing action before sub- 

 jection to the influence of sulphuric acid and heat. 



Two extractions with alcohol might prove sufficient if carefully 

 made, but it is safer to use three. To give the representations of 

 actual results yielded, 50 cub. centims. of sheep's blood were extracted 

 with alcohol. The first alcoholic extract contained 15 mgrms. of 

 glucose, the second 4, and the third no definite amount. Some sugar 

 from diabetic urine was added to sheep's blood, and 50 cub. centims. 

 taken. The first alcoholic extract was found to contain 144 mgrms. of 

 glucose, the second 9, and the third nothing definite. 



To prepare the alcoholic extraction for testing, the mixture of alcoholic 

 liquids obtained is acidified with acetic acid, heated to near boiling 

 point over the water-bath, and then filtered through ordinary filtering 

 paper. It is now brought down by heat to a small bulk, and treated 

 with an excess of crystals of sulphate of soda with the view of 

 causing the fatty matter finely dispersed through the liquid to agglo- 

 merate so as to be susceptible of removal by filtration. Water is 

 added to the surplus crystals of sulphate of soda, and a hot solution 

 made which is used for washing purposes. 



The titration of the product of alcoholic extraction with the 

 ammoniated cupric test gives quantitative results which stand in 

 complete accord with those I obtained by the gravimetric process, 

 which were mentioned in communications published in " Proc. Roy. 

 Soc," vol. 26, pp. 314 and 346. 



