Vol. 6, 1920 
PHYSIOLOGY: S. J. MELTZER 
535 
made before. The question now arose: Definite as the result is, is it 
important, that is, does it prove that the gangHa are really important to 
the maintenance of life, or was the fatal outcome perhaps due only to the 
operative procedure and not to the indispensability of some principle 
provided by the ganglia? Pulmonary lesions were found at the autopsy 
after the removal of both ganglia; pulmonary lesions are found after 
cutting both vagi. The ganglia are in the very proximity of the vagus 
nerves. May not the operative procedure injure both vagi sufficiently to 
bring about a "vagus pneumonia?" 
The following considerations and experimental facts speak against such 
an interpretation. The possibility of injuring the vagus nerves was taken 
into consideration at the very beginning of this study. As it was stated 
before, it was just on account of this possibility that rabbits were given 
the preference. In these animals the superior cervical ganglion is sep- 
arate from the vagus nerves, and it may be removed without touching the 
nerves or pulling at them. With this requirement in mind, I tried to 
carry out the experiment with care. It is not quite probable that I should 
have failed on both sides in nearly all my attempts, and that the injury 
which I might inadvertently have afflicted to both vagus nerves should 
have been of such an extent as to be equal in effect to a complete section 
of the nerves. Furthermore, in several experiments one of the gangHa 
could not be found and only one ganglion was removed. In these cases in 
which a long search for the gangHon was made the tissues and the cor- 
responding vagus nerve had to be quite severely manipulated. The 
animals nevertheless survived this procedure. Finally in some experi- 
ments, the lower half of both ganglia were removed, as mentioned before. 
Here the lower half was first crushed and then removed, which required 
more manipulations than the tearing out of the entire ganglion. These 
animals survived the operation without manifesting any untoward symp- 
toms. 
More direct and decisive evidence was obtained by stimulations of the 
central end of the vagus nerves after removal of the corresponding gan- 
glion, and after removal of both ganglia. The vagus nerves carry centri- 
petal as well as centrifugal nerve fibres. The centripetal fibres affect and 
control the respiration and cause a change in the state of blood pressure. 
Further, the vagus trunk and the superior laryngeal nerve, a branch of 
the vagus, carry fibres the stimulation of which causes reflex deglutition. 
The vagus nerve seems to contain also sensory fibres. The stimulation 
was effected by Faradic currents of various strengths. The procedure 
was as follows: One vagus nerve was cut and the normal effect of stimu- 
lation established ; then the corresponding ganglion was removed and the 
nerve again stimulated, and finally, the other ganglion was removed and 
the vagus stimulated. I shall state the results very briefly. 
Respiration. — Stimulation of the vagus nerve after removal of the cor- 
