PATHOLOGY: MELTZER AND WOLLSTEIN 
495 
animals died in less than twenty-four hours after receiving a certain (mini- 
mum) amount of the culture, while in the animals in which one vagus was 
cut four days before the injection or not cut at all, not a single animal 
died in such a short period, and most of them remained alive. In other 
words, a certain minimum quantity of culture which was injected ten 
or more days after one vagus was cut proved to be rapidly fatal; while the 
injection of the same quantity remained ineffective if no vagus was cut 
or was cut only a few days before the injection of the culture. 
We shall confine ourselves here to the communication of these facts 
and to only one interpretation of them. First, these experiments show 
unmistakably that the integrity of a certain form of nerve impulses is 
indispensable for the normal resistance of the lung tissue to infection or 
intoxication; if one vagus nerve was cut ten days before the injection of 
a pneumococcus culture a certain minimum of the culture was nearly in- 
variably rapidly fatal, while in a normal animal or in an animal in which 
one vagus was cut only a few days before the injection or not cut at all, 
the same minimum of culture has little or no effect. 
Second, for the vessels of most of the tissues it is known that they are 
innervated by vasoconstrictors and vasodilators. It is further known 
that the vasoconstrictors degenerate about four days after the section of 
the nerves, while the vasodilators degenerate only about ten days or later 
after the section. If we assume that the lungs are also provided with vaso- 
constrictors and vasodilators and that these vasomotor fibres are carried 
to the lungs in the vagus nerves, we would have a plausible explanation 
for the phenomena with which we were confronted in our experiments, 
namely, cutting of the vagi four days previous to the culture injection 
is capable of causing degeneration of only the vasoconstrictor nerve 
fibres, which may not be indispensable to the upholding of the normal 
activity of the lung tissue. If, however, the injection is made about 
ten days or longer after the cutting of one vagus, also the vasodilators 
are degenerated and their integrity may be indispensable for upholding the 
circulation and the normal resistance of the lung tissue to infection or 
intoxication by a virulent culture of pneumococcus type I. 
At any rate, our experiments brought out the facts that nerve impulses 
are running through the vagus nerves which are important to the uphold- 
ing of the normal resistance of the lung tissue itself. That even one 
vagus nerve is an important factor in this process; and that these activi- 
ties of the vagus nerves can be recognized only after an intrabronchial 
or intratracheal injection of a virulent culture ten days after the cutting 
of one vagus. 
