122 FURTHER INQUIRY INTO THE REASONS 
on this subject by my friends Ercolani and Vella, of Turin,, 
and by M. Colin, of Alfort. I shall conclude with such sug- 
gestions for further physiological and clinical inquiry as 
seem calculated to develop interesting and useful truths ; 
and with a view to aid those who may feel disposed to go 
deeply into the question, a bibliographical notice shall be 
appended. 
Previously to 1852, the question, why does the horse not 
vomit, had been the theme of discussion, and thus the cer- 
tainty of erring was involved in seeking a solution to a ques- 
tion wrongly stated ; for there can be no doubt, as a re- 
spectable number of recorded cases proves, that the horse does 
occasionally, though rarely, vomit. The cause of this rarity 
was the object of my research, which I commenced by thus 
analysing the doctrines previously advanced. 
1st. Dupuy in great measure attributed the difficulty of 
vomiting in the horse to powerful compression of the oeso- 
phagus by the muscular fasciculi of the right diaphragmatic 
crus ; but in the same manner as food passes freely down the 
oesophagus, no obstacle exists to its return so far as the 
aperture in the diaphragm is concerned. 
2dly. Lamorier and Gurlt referred to cardiac valves the 
impossibility of food passing back into the oesophagus from 
the stomach ; but neither the crescentic valve of the former, 
nor the spiral valve of the latter, exists in nature. 
3dly. I referred to M. Colin’s attempt to solve the question 
by applying to the horse’s stomach the theory of the 
hydraulic press ; and I remarked that “such a line of argu- 
ment is not justly applicable in the case of the stomach and 
oesophagus, which, as living and active organs, are not regu- 
lated solely by hydraulic laws.” I shall presently have again 
to refer to M. Colin’s analogical explanation, since he has 
repeated it in his treatise on ‘ Comparative Physiology,’ and 
sought to prove it by arguments and experiments equally 
founded, in my opinion, on insufficient basis, and employed 
in the solution of a physiological question with inadequate 
appreciation of vital forces and conditions. 
4thly. Bertin’s doctrine of a cardiac sphincter came 
under my consideration, together with the experiments and 
arguments with which it was sought to be definitively esta- 
blished by the perpetual secretary of the French Academy. 
Bertin stated, that when a horse’s stomach was removed 
from the body, filled with air or water, and tied at the duo- 
denum, the weight of a man did not suffice to expel the con- 
tents from the cardiac orifice. M. Fluorens repeated the 
same experiment twenty times, and found that even the 
