510 O. LARSELL AND M. L. MASON 
on autopsy, no other serious lung disturbance was noted, and 
they apparently died from other causes. Two of the animals 
which were subjected to the double vagotomy, however, died 
within forty-eight hours from respiratory difficulties due to 
closure of the glottis. 
The lungs of the four animals that survived gave results which 
were in such accord that they are believed to be typical. In 
these four animals the lungs were stained and treated by the 
procedure described in the article to which reference has already 
been made. In each case both lungs from a given individual, 
namely, the right normal lung and the left lung from the operated 
side, were carried through the various steps of technique together, 
in order to insure uniformity of treatment. It was believed 
that in this way the right lung, with its nerve intact, would serve 
as a check on the quality of staining of the nerve fibers in the left 
lung, the vagus fibers to which had been severed. 
A portion of the left vagus, including the neuroma at the level 
of the lesion, was also removed. ‘This was fixed in 0.5 per cent 
osmic acid, imbedded in paraffin by the usual process, and 
sectioned. Transverse sections 10u thick were made of portions 
from the proximal and distal ends, respectively, of the removed 
portion of the nerve, and longitudinal sections, mounted in 
series, were made of the remainder, including the neuroma. 
The corresponding portion of the right vagus was also re- 
moved from one animal, fixed and stained in osmic acid, im- 
bedded and sectioned transversely. It showed no indication of 
difference from the proximal end of the left vagus which was 
taken from the same animal (ef. fig. 1). There appears, there- 
fore, to have been no upward degeneration in the operated nerve. 
All of these nerves which had been subjected to operative 
procedure showed degeneration of the myelin sheaths below the 
level of section (fig. 2). In one animal (R7) there appeared a 
few rings in the distal part of the nerve (fig. 2, my.) which bore 
the semblance of normal myelin sheaths, as observed in trans- 
verse section, but these could not be followed consecutively 
through the series of sections, and probably represent only 
short stretches of myelin sheaths which had not yet completely 
