G. F. Barker—Physiological Chemistry. 21 
is changed into dextrin and then into sugar, by all those agents 
which convert ordinary starch into dextrin and sugar; pro- 
longed ebullition with dilute mineral acids, and the action of 
diastase and analogous ferments, such as exist in the pancre- 
atic juice, the saliva, and the blood, effect this change easily ; 
the opaline character of the solution disappears, it is no longer 
colored by iodine, it reduces alkaline solutions of copper, and 
ferments with yeast, yielding alcohol and carbonic acid. The 
diastasic ferments produce this change in 4 few minutes at the 
temperature of the body. Torrefaction, and the partial action 
of ferments or of dilute acids, change the glycogenic matter into 
a substance which, like dextrin, is insoluble in strong alcohol, 
is soluble in water giving a transparent solution, is not colored 
by iodine, does not reduce copper-tests, does not ferment, and 
rotates to the right the polarized ray. From the above results, 
Bernard argues that the formation of sugar in animals shoul 
be divided into two parts: the 1st—entirely vital, since it takes 
place under the influence of life—consists in the production of 
the glycogenic matter in the living hepatic tissue ; the 2d, en- 
irely chemical, is the transformation of this into sugar by 
means of a ferment. This ferment was at first supposed to 
belong to the liver, but finding that blood effected the change 
in a marked degree, Bernard referred it to this fluid. Durin 
digestion, the circulation is much more active, and the trans- 
formation of the glycogenic substance is correspondingly great; 
in torpid animals like frogs, on the other hand, where the cireu- 
lation is slow, the sugar disappears from the liver, while the 
elycogenic substance remains. If these animals be warmed, how- 
