212 
IOWA ACADEMY OF SCIENCE Voi,. XXVIII, 1921 
Fig. 31c. Frog 30, 7 days after unilateral section of the left vago-sympathetic 
nerve, showing total absence of the normal contour of the flank on the side of the 
nerve section only. Compare with the normal contour of the flank of the right side. 
21 days after the nerve section when the lung begins to be dis- 
tended by swallowed air, pushing out the flanks and finally form- 
ing ^'olive-shaped’' prominences. This readjustment was partial 
in all the animals with the exception of one, which lived for an 
extended period of a little over 8 months, the complete physiologi- 
cal readjustment occurring at the end of about months. In 
other animals living for periods of from 2 to 5 months, those of 
5 months standing always showed a greater degree of physiologi- 
cal readjustment than those of less duration. 
In recent bilateral vagotomized animals up to periods of from 
2 to 3 weeks air is found more constantly and usually in greater 
amounts in the stomach and intestine than in similarly operated 
animals of longer standing. This indicates that the air is forced 
into the stomach by the act of swallowing because of the persis- 
tently constricted lungs aided probably by a hypotonic stomach, at 
least in the early stages. 
