315 * 
ON EMETIN. 
By Hugh Ferguson, Esq., Temple. 
[We avail ourselves of the kind but unasked permission of the 
author to insert the following essay.] 
Experience and attentive observation, some years past, in- 
duced me to doubt the propriety of having recourse to aloes as a 
general remedial agent for reducing the inflammatory diseases 
affecting the principal respiratory organs of the horse. Aware 
of this drug being so strenuously recommended by the London 
Veterinary College as the safest nauseant that could be adopted 
in the practice of equine medicine, I instituted a number of ex- 
periments for the purpose of testing its efficacy in that character. 
The result of my investigations on the horse and other animals 
clearly demonstrated that the listless and languid slate of the 
patient, resulting from the exhibition of aloes, was more a symp- 
tom consequent on the localized irritation produced on the in- 
testinal mucous membrane, than of any specific effect on the 
nervous system through the medium of the circulation, and 
thereby exciting a true nausea, or tendency to vomit ; thus esta- 
blishing in my mind a marked physiological difference between 
the therapeutical operation of a nauseant and the languid list- 
lessness produced by aloes. The modus operandi of the one is 
quite at variance with that of the other : aloes in every dose having 
a tendency to increase the intestinal peristaltic motion in the na- 
tural direction from the stomach towards the anus; the intensity 
of the cathartic effect being, in a great measure, regulated by the 
dose ; and nauseants, on the contrary, tending to reverse the 
order of the intestinal peristaltic motion, and, when excess of 
this effect is produced, vomition is the result in those animals the 
formation of whose stomachs admits of the gastric contents being 
expelled by the oesophagus. Thus, the principal effect produced 
by the exhibition of the generality of emetic substances is dia- 
metrically opposed to that resulting from aloes. When given in 
a small dose they produce nausea, from being absorbed into the 
circulatory system by the veins and other vessels which carry 
their contents towards the heart, thus acting on the nervous sys- 
tem through the medium of the circulation; the intensity of the 
result, from a trifling nausea to the most violent vomition, being 
regulated by the degree of impression produced on the nervous 
system. If the dose be small in proportion to the animal’s power 
of resisting the action of the medicinal agent employed, the pe- 
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