FORMATION OF SUGAR IN THE LIVER. 
579 
menon. But when we analyse its mode of action we find 
that its effects are only mechanical, and are brought first to 
the motor organs of the capillary circulation, the effect of 
which has been to lessen or hinder, or else to extend and 
augment the contact of two substances capable by their pro- 
perties, of reacting one on the other; they thus produce a 
chemical phenomenon which the nervous system regulates 
indirectly, but upon which it has no direct and primitive 
action. This view is not peculiar to the liver, and I shall 
prove further on that the chemical influences which are re- 
cognised in the nervous system in general are most commonly 
purely mechanical. 
As for the conclusions which we can at this moment 
deduce, in a general physiological point of view, from the 
mechanism which we have indicated for the formation of 
sugar in the liver, it is impossible not to be struck with the 
similarity which exists in this respect between the glucogenic 
function of the liver and the production of the sugar in 
certain acts of the vegetable organism. In a seed, for 
instance, which produces sugar during germination, we have 
likewise to consider two series of very distinct phenomena; 
the first primitive, entirely vital, is constituted by the 
formation of starch under the influence of the life of the 
vegetable ; the other consecutive, entirely chemical, which 
may take place without vegetable life, is the transformation 
of the starch into dextrine and sugar by the action of diastase. 
When a liver taken from a living animal continues for a cer- 
tain time to produce sugar, it is evident that the vital 
phenomenon of the creation or secretion of the glucogenic 
matter has ceased ; but the chemical phenomenon continues 
to be produced if the conditions of humidity and heat neces- 
sary for its accomplishment are realised. In the same way, 
in the seed separated from the plant, the vital phenomenon 
of the secretion of starch has ceased with the vegetable life ; 
but, under the influence of favorable physico-chemical 
conditions, its transformation into dextrine and sugar by 
means of diastase may be produced. Finally, it is easily 
seen from these parallel observations, that the formation of 
sugar in the liver of animals passes through three series of 
successive transformations in every respect analogous to that 
of the formation of starch, dextrine, and sugar in the seed of 
vegetables. 
According to all the facts contained in this work, we may 
conclude that the question of the formation of sugar in 
animals has made an important step in advance, in con- 
sequence of the isolation of the glucogenic matter which 
