1881.] Physiology of Sugar in the Animal System. 421 



The total of these results is that Bernardiu (glycogen) equivalent 

 to 4*085 grms. of glucose was added to 705 cub. centims. of blood, 

 and that the amount of sugar produced was 0*194 grm. I do not 

 know the reason of the figures standing so much, higher in experi- 

 ments 11 and 12 than in any of the others. The two were conducted 

 together and with the same specimen of blood, which was only used in 

 these particular experiments. 



The amount of sugar produced is too insignificant to be susceptible 

 of recognition by ordinary testing. Half a gramme of a sample of 

 Bernardin (glycogen), standing equivalent to 0*367 grm. of glucose, 

 was mixed with 25 cub. centims. of blood, and exposed for half an hour 

 to 100° F. Prepared for testing with heat and sodic sulphate in 

 the ordinary way, the product gave with the cupro-potassic test no 

 visible indication of the production of sugar. 



The point shown by these experiments is that Bernardin (glycogen) 

 may be brought into contact with blood and kept in contact, for some 

 time, at a temperature equal to that of the living body, without under- 

 going conversion into sugar to more than what may be spoken of 

 as quite an insignificant extent. Not only do the quantitative deter- 

 minations of sugar prove this, but there is the further conclusive fact 

 that the Bernardin is subsequently recoverable from the blood. The 

 ground is therefore cleared in such a manner as to show that there is 

 nothing inconsistent with Bernardin existing in and constituting a 

 natural element of the blood. 



Having established this foundation, I will now proceed to deal 

 with the blood as it exists in the body, investigated in relation to 

 Bernardin. 



It is only when light begins to dawn upon a subject that the path of 



thousands of times ; and if an experience of this kind will justify an expression of 

 opinion, I may state that I am satisfied it will be found invaluable alike to the phy- 

 siologist, the chemist, and the physician. 



The test is prepared by adding ammonia to a cupro-potassic solution, for which 

 the following is the formula : — 



Cupric sulphate 34*65 grms. 



Potassic sodic tartrate (Rochelle salt) 170 ,, 



Potash 170 „ 



Water to 1 litre. 



For the ammoniated test 120 cub. centims. of the above solution are mixed with 

 300 centims. of strong ammonia (sp. gr. 0*880), and water added to a litre. 20 

 cub. centims. of this ammoniated cupric liquid are decolorised by 0*010 grm. of 

 glucoss. 



The liquid to be examined is allowed to drop from a burette into a suspended flask 

 containing the test, which is kept briskly boiling till decoloration has been attained. 

 The reduction being attended with decoloration without precipitation, there is 

 nothing to obscure the determination of the moment when the precise point wanted 

 has been reached. 



