ANAISTHESIA OF THE HORSE. : 31 
especially characterized by the disappearance of conjunctival reflex 
and atresia of the pupil. When anesthesia is carried to that ex- 
tent the touching of the conjunctiva and of the cornea no longer 
stimulates the action of the orbicular palpebral—the last reflex of 
animal vitality. For this reason it is considered by all surgeons as 
the true regulator of anesthesia. When it has ceased to be present 
and as long as it remains absent the inhalations must be. suspended, 
to be renewed again'as soon as it reappears. This sign is of the 
greatest value, for it characterizes complete anesthesia, and the mo- 
ment it appears the case is known to be yet far from the period of 
toxic accidents. The variations of the pupil give also useful indi- 
cations. As anzesthesia progresses, the pupil, which had dilated 
(mydriasis) in the period of excitement, contracts (myosis) ; it re- 
mains narrow and immovable as long as the sleep lasts, and slowly 
‘dilates again as sensibility returns. Its sudden dilation during an 
advanced stage of anesthesia is a sign of bulbar intoxication, and 
threatens syncope. 
When palpebral reflex has ceased and the pupil is contracted, sen- 
sibility has disappeared and muscular relaxation is complete. Ifres- 
‘spiration and circulation take place in a regular way, anesthesia may 
be continued for a long time without danger, by adding now and 
‘then new doses of ether. 
The operation ended, the hobbles are removed from the patient, 
he is left to himself until he wakes and gets up. 
In order to avoid the waste of ether, which is very volatile, the 
apparatus of Junker, used by some to administer chloroform, has been 
‘recommended. In its simplest form this apparatus consists of a 
graduated glass containing the aneesthetic, and closed with a cork 
perforated with two holes, through which are introduced two bent 
glass tubes. One of these, dipping in the liquid, carries on the other 
end a Richardson bellows (s) ; the other tube, which is shorter and 
-does not reach the liquid, carries at the otherend a pear-shaped ball 
-(r), which is introduced into the nostril. (Fig. 27.) As soon as the 
Richardson bellows is squeezed, air is pushed into the liquid and 
‘loaded with anesthetic vapors and bubbles, and is carried to the 
‘respiratory organs, without waste, through the othertube. Narcosis, 
‘however, is quite difficult to obtain with this apparatus, even in 
‘using one for each nostril. To make the instrument more portable, 
the glass tubes have been replaced by metallic ones, and the gradu- 
ated glass has been provided with a metallic hook, to hook it to the 
button holes of the assistant who administers the anesthetic. > In- 
halers with valves were discarded. long ago. Leather | muzzles, 
metallic masks, sacciform inhalers, are less in use than compresses. 
Often to produce sleep a large quantity of ether must be adminis- 
-tered—z50 to 500 grams. andeven more. The waking up with ether 
