eo 
1886.1 Physiology. 399 
than that of the portal vein, not only during hunger, but after all 
manner of carbohydrate diet. The formation of sugar in the liver 
has nothing to do with the sugar ingested with the food. The for- 
mation of sugar by the liver persists throughout a prolonged 
period of inanition, and is not increased when a large amount of 
carbohydrate is fed to the animal. Seegen does not believe that 
the glycogen found normally in the liver is the source of the 
sugar of the hepatic vein; it probably has some special destiny, 
perhaps the formation of fat. The amount of glycogen found in 
the liver stands in very close relation to the amount of carbohy- 
drate in the food.— Pfiiger’s Archiv., 1885, pp. 325 and 348. 
PLETHYSMOGRAPHIC AND VASO-MOTOR EXPERIMENTS WITH FROGS. 
—Dr. Ellis has followed Drs. Bowditch and Warren in a series of 
investigations which bids fair to open the way to much that is 
new and-yaluable concerning the vaso-motor mechanism. The 
latter observers studied by the graphic method the variations of 
volume produced in the hind leg of a curarised cat by electrical 
Stimulation of the sciatic nerve. The volume of the limb was 
measured by the plethysmograph, and any fluctuations in it could 
o due to variation in the amount. of blood supply. The 
authors found when the peripheral end of the nerve was excited 
by rapidly repeated induction shocks (16-64 per sec.), there was 
usually contraction of the vessels. When a slower rate was 
employed (4-0.2 per sec.), there was dilatation. With a medium 
rate of stimulation there followed first a narrowing and afterward 
a dilatation. A latent period of 1.5 sec. preceded the constriction, 
and one of 3.5 sec. the dilatation. The latter effect sometimes per- 
sisted for several minutes after cessation of the stimulation, but 
the former usually ceased with it. 
By an exceedingly ingenious application of a test-tube ple- 
thysmograph connected with v i 
ours, Dr, Ellis has been able to study the vaso-motor changes 
ing the varying effects of electrical stimulation upon the 
blood-vess à 
= greater the tendency to immediate dilatation. 2. The 
eck. f induction shocks per second. ‘The greater the number of- 
per second, the greater the liability to contraction, and 
sOnwersely. 3. Duration of the stimulation. The longer a series — 
a Measure true, namely, the weaker the stimu- — y 
