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cardia usually disappears, either on account of the reduction 
of the amount of bile acids in the blood or because the heart 
becomes accustomed to their effect. If we take into considera- 
tion the usual appearance of gastric complications accompanying 
catarrhal conditions in the bile ducts, it is difficult to say whether 
these cardiac manifestations are the result of liver disease or 
of the stomach complication. 
The factors that may be responsible for the production of 
cardiac reflex symptoms due to disturbance of remote organs 
may be grouped under the following heads: (1) Mechanical, (2) 
chemical, (3) psychic. 
Mechanical factors. — The mechanical theory may be explained 
in two ways; either by encroachment of the distended stomach 
on the space occupied by the heart, or by the mechanical irrita- 
tion of the nerve endings on the wall of the stomach, produced 
by the stretching of the wall. Mere overloading is not always 
followed by such symptoms; they may be present without dila- 
tation or distention. 
Chemical factors. — The chemical causes may be endogenous 
or exogenous. The endogenous may be toxic substances which 
originated in a perverted digestion, or may be certain internal 
glandular secretions or homones which, when present in the 
blood in larger amounts than normal, may disturb the heart 
action without necessarily causing pathological change in the 
organ. They may act, however, in manifold ways on the cen- 
tral nervous system, on the intrinsic nervous mechanism of the 
heart, or on the heart muscle itself. 
The exogenous chemicals, like nicotin, atropin, and others, 
have no place here, as we are discussing only disturbances in 
the body itself that are accompanied by cardiac reflex symptoms. 
Psychic factors. — The psychic factors are probably ultimately 
chemical. We have the experiments of Cannon and De la 
Paz 4 about the increase of epinephrin in a cat by psychic excite- 
ment, as rage, fright, etc. The subject of emotion is a com- 
plicated one. 
In conclusion, no one of these factors is the only one respon- 
sible for the production of the cardiac reflex symptoms ; but all 
or one of them may play some role in producing the symptoms 
in individual cases, and in many instances one or all of them 
may help to cause the cardiac syndrome designated under the 
name of cardiac reflex symptoms. 
4 Cannon, W. B. and De la Paz, D., Emotional stimulation of adrenal 
secretion, Am. Journ. Physiol. 28 (1911) 64-70. 
