ON THE CHOKING OF CATTLE. 
445 
especially about the larynx, and ordered small doses of tartarized 
antimony to be given every few hours. The blister acted well 
upon the throat, the bowels were soon relieved, and' the inflam- 
matory action subsided rapidly. In three or four days she ap- 
peared nearly well, with the exception of a slight cough, and no 
other untoward appearances occurred, except that she calved a 
week prematurely ; both cow and calf, however, did well. 
Having thus given a short account of those cases which have 
come under my observation, in which imminent danger threatened 
from the improper administration of medicine or other substances, 
the remarks which I shall offer upon them naturally arrange them- 
selves into two groups — the first connected with the causes of the 
evil, the second with its effects : the cause, of course, comes first. 
To make the subject plain, especially to the non-professional 
reader, it seems necessary to give a short outline of the anatomy 
and physiology of the organs of respiration (breathing) and deglu- 
tition (swallowing), in as far as they are related to each other. 
The passage of the inspired air to the lungs is through the nasal 
chambers or nose, the pharynx, larynx, and trachea or windpipe ; 
that of the food from the mouth to the stomach is through the 
fauces, pharynx, and oesophagus or gullet. Now, it has to be no- 
ticed, that when the head and neck are extended in a horizontal 
position, the air-passages lie uppermost in the face and anterior 
part of the head; but in the posterior part of the head and along 
the neck, the food passage or gullet lies uppermost. In consequence 
of this arrangement, it is plain that the two passages have to cross 
each other, and this they do in the pharynx, the cavity or pouch 
of which is their common point of intersection. This e crossing may 
be not inaptly compared to an inverted letter b p^ c d a being the 
mouth, b the nostrils, c the oesophagus or gullet, d the trachea or 
windpipe, and e the cavity of the pharynx, into which both the 
superior and inferior food and air-passages open. From this de- 
scription it will be seen, that both the breath and food pass through 
one common opening, the pharynx. It is also obvious that, if 
respiration and swallowing went on at the same time, there would 
be a general mixing of the ingesta, whether food or drink, with 
the air going to the lungs, and consequently a continual choking. 
Let us examine, therefore, the precautions which Nature has 
adopted to prevent such an evil. In the first place, the glottis and 
epiglottis, which form the upper and terminating portion of the 
larynx, and which are designed only for the transmission of air, 
are covered by a delicate and highly sensitive membrane furnished 
with involuntary nervous sensation, so that warning is given by 
their immediate closure of the presence of any intruding foreign 
body, without the round-about course of awaiting a command of 
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