BILATERAL, VAGOTOMY OF FROG 
213 
Fig. 31d. Same animal as in figure 31b, 32 days after bilateral vagotomy, showing 
a partial physiological readjustment of the peripheral lung motor mechanism. Note 
the “olive-shaped” prominences. 
All the autopsy findings confirmed the above results. 
Bilateral vagotomy has little or no effect on the buccal move- 
ments, whereas the actual respiratory movements (opening of 
glottis and swallowing of air into lungs) are temporarily abolished, 
but these movements gradually return with the physiological re- 
adjustment of the peripheral lung motor mechanism. 
The lung readjustment in these long time experiments is not due 
to a gradual weakening of the animals from age and starvation 
since animals when fed and kept in close confinement react in a 
similar manner after unilateral or bilateral vagotomy as do nor- 
mal animals which have not been so kept. Furthermore, the fail- 
ure of the vagotomized lungs to contract down to practically a 
solid mass on death or destruction of the medulla in these experi- 
ments is evidence that this readjustment is not due to a vagus 
regeneration. It may be implied, therefore, that this physiological 
readjustment of the vagotomized lung is brought about through 
some special activity of its peripheral neuro-muscular mechanism. 
