762 DISEASES OF THE STOMACH AND INTESTINES. 
cause, we are compelled to conclude the nervous system to 
be primarily concerned ; the disturbance of the circulation will 
follow as a matter of course. It is difficult to explain how 
this occurs—why a diffused impression of cold should be 
followed by vascular derangement; but the fact is beyond con¬ 
troversy, that many catarrhal affections, and congestive and 
inflammatory diseases, proceed from a commencement so 
apparently trivial. 
In discussing this question, it must not be forgotten that 
the appearance of the symptoms of shivering often indicates 
the establishment of the disease, so that it has a claim to be 
considered as a result as well as a cause of the morbid 
changes. Pursuing the argument to its legitimate termi¬ 
nation, we are justified in asserting that cold, produced either 
by direct contact with a medium of low temperature, or by the 
evaporation of moisture from the surface, has a tendency to 
occasion derangement of the circulation in the internal organs, 
amounting to determination, congestion, or inflammation, 
according to the intensity of the cause, and the predisposition 
existing in the system at the time of its action; secondly, that 
a diminution of animal heat is the necessary result of a pre¬ 
ponderance of the congestive element, or of a deficient circu¬ 
lation in the vessels of the skin. 
Exposure, shortly after the use of calomel, has been before 
alluded to as particularly likely to lead to an attack of acute 
diarrhoea; no reasonable explanation of this circumstance 
suggests itself to us ; but the popular belief that mercury in 
any form renders the animal body particularly susceptible to 
the action of cold is certainly not without good foundation. 
Irritating alimentary matter, or medicinal agents, are for 
obvious reasons capable of exciting this form of the disease, 
and in the horse especially there seems to be an irritable 
condition of the intestinal membrane in every instance of 
febrile affection, that makes it impossible to employ agents 
even in small doses that exert a comparatively slight influence 
in a state of health. The effects of the injudicious adminis¬ 
tration of aloes, during the existence of pleuropneumonia, or 
influenza, or bronchitis, and sometimes even in common 
mucous catarrh, may be advanced as an evidence of the 
extraordinary susceptibility of the mucous membrane to 
irritating influences. 
After the administration of the salts of antimony, particu¬ 
larly the potassip-tartrate, a moderate dose of aloes will often 
occasion violent superpurgation; and on the other side, purga¬ 
tion once established by the action of aloes, may be seriously 
increased by small doses of the tartar emetic. 
