THE READJUSTMENT OF THE PERIPHERAL LUN.G 
MOTOR MECHANISM AFTER BILATERAL VAGOTOMY 
T. L. PATTERSON 
It has been shown by Carlson and Luckhardt (1) in crucial 
experiments (1 to 2 hours) that destruction of the medulla or 
section of the vagi in the frog leads immediately to a permanent 
hypertonus or incomplete tetanus of the lung neuro-muscular 
mechanism, which makes the lung practically non-functional and 
useless as a respiratory organ. The present work however, was 
undertaken with the idea of ascertaining whether this hypertonic 
condition observed by these authors is permanent or temporary. 
The older literature dealing with the respiratory movements of 
the frog, which it is not necessary to go into here, is more or less 
conflicting and inadequate in itself to explain the true lung re- 
action resulting from destruction of the medulla or section of the 
vagi and needs re-investigation, especially in view of the recent re- 
sults of Carlson and Luckhardt in acute experiments. 
The anatomy of the frog’s lung is well known, it being a paired 
muscular sac having numerous muscular septa on the interior sur- 
face dividing it into small spaces or alveoli. The septa extend 
only a few millimeters from the lung wall, so that the larger part 
of the lung cavity is a large single air space. There are no 
bronchi and no true trachea, the tracheal sac having essentially 
the same structure as the rest of the lung and probably carrying 
the same respiratory function. The entire wall of the lungs is 
covered with smooth musculature which extends into the smallest 
septa on the inner surface, while more or less definite external 
muscular strands follow the course of the main pulmonary blood 
vessels on the lung surface. The lung musculature is so arranged 
that contraction, even of the septal musculature, will reduce the 
size of the lung cavity, or raise the intrapulmonary pressure in 
of the septal musculature would be analogous to that of the bron- 
case the air in the lung is not free to escape. Hence, the action 
chial constrictor muscle of the mammalian lung. 
According to the histological studies of Arnold (2), Smirnow 
(3), Cuccate (4) and Wolff (5) there are numerous ganglia, as 
