1893.] The Glucoside Constitution of Proteid Matter. 53 



VI. "The Glucoside Constitution of Proteid Matter." By 

 F. W. PAVY, M.D., F.R.S. Received May 20, 1893. 



(Abstract.) 



For a long time I have adopted a process for separating the glyco- 

 gen of the liver consisting in boiling with potash, pouring into alco- 

 hol, and collecting the precipitate. For the purpose of estimation, 

 the precipitated glycogen was converted by means of sulphuric acid 

 into glucose, the determination of which gave the information re- 

 quired. I afterwards applied the process to blood, and the various 

 organs and tissues of the body, with the result that a more or less 

 notable amount of cupric oxide reducing product was obtained, which 

 I at the time looked upon as taking origin, as in the case of the liver, 

 from glycogen. 



When small quantities were operated upon for quantitative 

 analysis, I experienced no difficulty in obtaining the product looked 

 for. When large quantities, however, were taken for the purpose of 

 collecting it and studying its properties, I invariably failed to obtain 

 anything like the amount that ought to have been yielded according 

 to the indications afforded by the quantitative analysis conducted. 

 These attempts were undertaken at different times upon blood, eggs, 

 and the spleen. It was obvious there was something connected with 

 the extraction with which I was not acquainted, and it was through 

 prosecuting inquiry to clear up the discrepancy that I came across 

 the knowledge revealed in this communication. 



Detailed particulars are given in the communication of experiments 

 with various animal and vegetable proteid matters, showing that the 

 amount of cupric oxide reducing product obtained after the applica- 

 tion of the potash process varied through the instrumentality of the 

 potash. If free glycogen or starch had been the source of it, the 

 treatment with potash should have produced no effect beyond dis- 

 solving the associated nitrogenous matter and placing it in a position 

 to be separable by the agency of the alcohol, and no difference should 

 have resulted from varying the strength of the alkali or the length of 

 time of contact. The results obtained led to the conclusion that the 

 cupric oxide reducing product must have taken origin from some 

 other source than free glycogen or starch, and pointed to its having 

 been derived from a cleavage of the proteid molecule. 



The steps of procedure employed for obtaining the product sus- 

 ceptible of conversion into a cupric oxide reducing body (sugar) 

 from proteid matter are described at length, and an account given of 

 the difficulties which had led to a want of success in my early 

 endeavours to collect the body in quantity. With the knowledge 



