578 FORMATION OF SUGAR IN THE LIVER. 
this matter does not appear to correspond with it at that 
moment. This circulatory super-activity may likewise be 
awakened without digestion ; and then the same phenomena 
of transformation of the matter and appearance of the sugar 
take place. Among hibernating or benumbed animals, such 
as frogs for instance, the slackening of the circulation, which 
is connected with a lowering of the temperature, causes a 
diminution, and sometimes the almost entire disappearance 
of the sugar from the liver. But the glucogenic matter is 
there all the same, as may be proved by extracting it. It is 
then only necessary to put the benumbed frogs in the 
warmth to render their circulation active, and the sugar then 
soon appears in the liver. On placing the animals again in a 
low temperature we find that the sugar diminishes, or disap- 
pears to show itself again when the frogs are again placed in 
a warmer place. I must add that these singular alternations 
of the appearance and disappearance of the sugar may be 
reproduced several times without the animals having any 
food, and by acting solely on the phenomena of the cir- 
culation by the intermediation of the temperature. 
In warm-blooded animals we can also act, by means of the 
nervous system, on the phenomena of the abdominal circu- 
lation, and afterwards secondarily on the transformation of 
the glucogenic matter in the liver. I have shown that if we 
cut or wound the spinal marrow in the region of the neck, 
below the origin of the phrenic nerves, we considerably 
diminish the activity of the hepatic circulation, so much so 
that after four or five hours there are no traces of sugar in the 
liver of the animal, the tissue of which still remains charged 
with glucogenic matter. It is remarkable that after this 
operation the temperature of the abdominal organs falls con- 
siderably, at the same time many other perturbations are 
produced of which I cannot now stop to speak. 
I have likewise proved that by wounding the cerebro- 
spinal axis in the region of the fourth ventricle, we produce 
exactly contrary phenomena ; the abdominal circulation is 
very much accelerated, and consequently the renewal of the 
contact of the glucogenic matter with its ferment con- 
siderably extended. The transformation of the glucogenic 
matter moreover becomes so active, and the quantity of sugar 
removed by the blood becomes so considerable, that the 
animal, as is well known, becomes diabetic in this case, that 
is to say, that the excess of sugar poured into the blood by 
the super-excited liver passes into the urine. 
In these two cases the nervous system acts evidently on 
the purely chemical manifestation of a physiological pheno- 
