ACTION OF STIMULANTS IN CONGESTION OF THE LUNGS. 501 
Applying the evidence which is gained by microscopic 
investigation of the development and progress of congestion 
in a membrane^ to the occurrence of the same abnormal state 
in the lungs, it may be assumed that the vis a ter go has but 
comparatively little influence in the production of the disease. 
In all probability it is of no consequence what quantity of 
blood is driven into the lungs, so that motion continues and 
the fluid is properly oxygenated; and if from any cause these 
essential functions are interrupted, retarded or arrested 
motion of the fluid will result, without reference to the 
quantity which may at the time be contained in the vessels 
of the part. Congestion is distinguished from inflammation, 
not by the difference in the amount of blood in the vessels, 
but absolutely by the difference in the rate of motion. 
The final result of arrestation of the blood^s motion is 
death, from suspended function, and this fatal consequence 
is to be prevented, not by exciting the heart to an increased 
effort to drive on the accumulated blood, but by the employ¬ 
ment of stimulants and restoratives to rouse the failing 
powers of life, and increase the molecular activity of the vital , 
fluids. Ammonia or its carbonate exercises this desirable 
effect in a positive manner, producing a general excitation 
without any narcotic action, and probably also causing a 
beneficial effect upon the blood by preventing its solidifi¬ 
cation. 
The therapeutic action of stimulants, and particularly of 
ammoniacal compounds, in congestion of lungs, cannot con¬ 
sistently be ascribed to their dynamic effects upon the 
circulation, but to their influence upon the nervous system. 
There is no evidence of the assumed power of such agents to 
increase the force of the hearths action in an especial manner, 
and there is no reason to conclude that if the effect were 
produced it would tend to cure the disease. 
Practically, there is no doubt of the therapeutic properties 
of ammonia and its carbonate in pulmonary congestion, and 
it is in strict accordance with the ascertained facts in patho¬ 
logy to ascribe this beneficial action to the solvent property 
of the agent in reference to the constituents of the blood, and 
the stimulant or restorative effect upon the nervous system. 
