212 
RICHARD MIDDLETON. 
ance of his oats. No new attack was noticed during the next 
three days, and the horse was put to work. More for the 
purpose of quieting the owner, than with the expectation of 
receiving any benefit therefrom, a course of treatment was in¬ 
stituted which consisted in doses of ext. hyoscyamus given in 
electuary. 
The cause of the dyspnoea in both these cases is a mystery. 
When we consider that the heart and lungs of both patients 
were sound, and that in other respects their functions were in 
no degree deficient, we are justified in coming to the conclu¬ 
sion that the cause was a temporary one, dependent upon 
transitory circumstances which were instrumental in affecting 
an irritation upon the respiratory center. A relationship be¬ 
tween these cases and asthma, hysteria and similar attacks de¬ 
pending upon neuroses, cannot be admitted, because the latter 
affections are of the recurrent and chronic nature, and mani¬ 
fest themselves from time to time. 
According to physiology, the center which presides over 
the rythmical movements of the lungs, is situated in the 
medulla oblongata, at the point of origin of the vagu and ac¬ 
cessorius nerves ; up to the present time it has not been deter¬ 
mined whether the activity of the same is automatic, or reflex. 
But experiments make it apparent that there are reflex fibers 
in the constitution of the tenth pair. Through these irrita¬ 
tions the pulmonary movements are influenced in either an in¬ 
hibitory or an excitative manner. The former is brought 
about by the expanded lungs; the latter by the collapse of 
those organs. In this manner a self-regulation of respiration 
is generated, and a compensatory rythmus obtained. 
All diseases of the lungs, heart, and their surrounding 
membranes modify the rapidity and depth of the breathing ; 
another factor which is active in bringing about the same end 
is a condition of incomplete decarbonization of the blood. 
The disproportion in the gaseous constitution of the blood 
must not of necessity involve the blood in all vessels ; it is 
sufficient when this poverty is local and confined to the vessels 
of the medulla ; when e. g. through a hinderance of any kind 
a retarding of the venous flow from the brain, by which the 
blood is richer in carbon dioxide and destitute of oxygen. 
