PAR VAGUM. 
duced evidence to shew that these morbid 
changes do not necessarily follow the division 
of both vagi in all animals, and that the dog in 
a few rare cases may either die of inanition 
from the arrested secretion of the gastric juice 
and without any morbid alterations in the 
lungs, or may even survive the operation and 
recover from its effect. 
Magendie, Wilson Philip,* Mr. Swan,+ and 
Longet,j found that section of one vagus in- 
duced diseased action in the lung of the same 
side. The lesions observed by these experi- 
menters differed very considerably in their 
character. Dupuytren,§ on the other hand, 
could discover no alteration in the lung of the 
side on which the vagus had been divided in 
two dogs and a horse, though these animals 
were allowed to live more than a month. In 
an experiment made by Magendie before his 
pupils, the results were completely at variance 
with his former expressed opinions. The right 
lung of a dog was found perfectly healthy, 
though a portion of the vagus of that side was 
removed six months before.|| We have re- 
moved a portion of one vagus in seventeen 
animals, and allowed them to live a longer or 
shorter period,—from twenty-four hours to six 
months,—and in none of these could we detect 
any morbid changes in the lungs which we 
could attribute to the injury of the nerve. This 
immunity of the lung from the usual morbid 
changes, when one nerve only was divided, we 
attribute to the smaller diminution of the 
respiratory muscular movements, than when 
both nerves are divided. 
Functions of the gastric branches. _ Do 
the gastric branches of the vagus contain 
some, motiferous filaments ?—Mr. Mayo] and 
Miiller** failed in exciting muscular contrac- 
tions in the stomach by irritating the trunks of 
the vagi, while this experiment succeeded in the 
hands of Bichat,}+ Tiedemann and Gmelin, tt 
and Longet.§§ Breschet and Milne Edwards|||| 
inferred that muscular movementscan be excited 
in the stomach of a living animal by galvanizing 
the lower end of the divided vagi in the neck 
from its effects upon the digestive process. We 
have carefully and repeatedly performed the ex- 
periment of irritating the vagi, and are confident 
that though it occasionally fails, yet it often suc- 
ceeds.§] These muscular movements in thesto- 
mach differ considerably from those in the ceso- 
phagus. They are more slow and are vermicular. 
* Experimental Inquiry, &c. p. 145. 
+ Essay on the Connection of the Heart and the 
Functions of the Nervous System, &c. 
Opus cit. p. 351. 
t ; Biblioth. Méd., 1807, 
quoted by Longet. 
|| Legons sur les Phénoménes Physiques de la 
_ vie, tom. i., p. 203-4. 
__ 4 Anatomical and Physiological Commentaries, 
i No. 2, p. 15. 
__ +** Elements of Physiology. 
tt Anatom. Générale, tom. iii., p. 360. 
t. xvil., p. 21., as 
Paris, 
_ _ tt Recher. Experim. Physiol. et Chem. sur la 
Di estion, p. 374. 
' § Opus cit., p. 322. 
| Archiv. Gen, de Méd., tome vii. 
ra { Opus cit. 
899 
They generally commence at the cardiac orifice 
and proceed to a greater or less extent towards 
the pyloric orifice. Longet thinks that he can 
explain this discrepancy in the results of this 
experiment, as he found that it succeeded 
when the stomach was engaged in the process 
of chymification, and failed when it was empty. 
Though we are satisfied that the gastric branches 
of the vagus contain some motor filaments, yet 
we do not believe with Breschet and Milne 
Edwards, Brachet, Longet, and others, that the 
muscular movments of the stomach depend 
entirely upon the integrity of the vagi. Ma- 
gendie* observed these muscular movements 
continue after section of the vagi; and we ascer- 
tained from experiment that if a dog recovers 
from the first effects of the operation of cutting 
the vagi, the stomach can still propel the chyme 
onwards into the duodenum. Arnold,+ from 
his experiments upon hens and pigeons, con- 
cludes that the contractions of the stomach are 
less influenced than those of the esophagus and 
crop by division of the vagi. The grains taken 
into the stomach after this operation were found, 
however, to be considerably less bruised than 
in sound animals. 
Effects of lesion of the vagi upon the sensa- 
tions of hunger and satiety —Though the sensa- 
tion of hunger is referred to the stomach, yet it 
is evident from well established facts that this 
sensation is actually situated in the encephalic 
portion of the nervous system. ‘This sensation 
1s not dependent, as far as we know, upon any 
‘physical condition of the stomach itself, and in 
all probability arises from certain organic 
changes in the body, connected with the want 
of additional supplies of nutritious matters 
from without. Brachet relates two experiments 
to show that the sensations of hunger and 
satiety are arrested by section of the vagi,t but 
these are liable to certain sources of fallacy 
against which proper precautions were not 
taken. Four of seventeen dogs we experimented 
on, lived: beyond the fifth day after the division 
of the vagi, and exhibited no signs of having lost 
the sensation of hunger; on the other hand 
their actions indicated that they still retained 
this sensation. Longet has from his experi- 
ments arrived at conclusions on this point 
similar to ours.§ There can be no doubt that 
the sensation of hunger is almost always sus- 
pended for a longer or shorter time after the 
division of the vagi, probably occasioned in 
some measure by the pain and terror attending 
the operation, but if the animal live for a few 
days the sensation of hunger may return. 
Though the facts from which Brachet has 
arrived at the conclusion that the sensation of 
satiety is annihilated by the division of the vagi, 
do not, as we have elsewhere shown,|| warrant 
this inference, yet it is probable for reasons 
which will occur to every one in reflecting 
* Compendium of Physiology. 
Milligan, 4th edit., p. 261. 
+ Bemerkungen tiher den Bau des Hirns und 
Riickenmarks, &c., S. 145. 
+ Systéme Nerveux og ge Expt. 52-3. 
Opus cit., tom. ii., p. 329. 
i Opus cit. 
Translated by 
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