140 
DR. A. WALLER ON THE MINUTE STRUCTURE OF THE PAPILLA 
respiration. It likewise acts as an agent for seizing prey by being rapidly thrown 
out of the mouth, and enveloping the object to be laid hold of. In this act it is pro- 
truded from the mouth by turning round the lower jaw bone as a centre of rotation, 
the upper surface then becoming lowermost. The lingual arteries and veins are 
derived from the same trunks as in man, ascend the throat parallel to each other, 
and enter the tongue between the hyoglossus and the genioglossus. The nerves con- 
sist of two pairs, one direct from the brain, the other from the spinal marrow. 
Mode of 'preparing the Frog's Tongue for examination. 
In former experiments I confined the animal in a narrow bandage, which I rolled 
round it from the feet to the neck. In this state all movement of the limbs was com- 
pletely prevented, while it was still able to carry on respiration. A piece of sheet 
cork, about the breadth and length of the animal, was then provided, and an open- 
ing made near one end of about the size of a shilling. After being secured to this 
cork, the tongue was turned out of the mouth and stretched over the opening by 
means of pins. But notwithstanding every care that could be taken it frequently 
happened that the experiment would be interrupted by the movement of the tongue, 
and its being torn from the pins. I am now able, by submitting the animal to the 
action of ether, to avoid these objections. For this purpose I find it most convenient 
to place the frog in a large wide-mouthed bottle, closed with a ground stopper, and 
containing ether. To prevent the contact of the ether with the animal’s body, 
where it would produce inflammation, I keep the ether apart in a small phial, which 
is introduced into the bottle, so that in all the animal’s movements it never is affected 
by the liquid. Placed in this kind of closed chamber, the frog becomes quickly 
narcotized by the ethereal atmosphere. The cessation of all motion shows the period 
when insensibility has taken place, and it may be withdrawn and the tongue ex- 
panded around the opening as before described. Usually the animals are completely 
insensible after about five minutes’ exposure, and remain in that condition for upwards 
of half an hour. The insensibility may be prolonged to several hours by leaving 
them longer in the bottle. An exposure of half an hour generally renders them in- 
sensible for two hours. In this way we have the great advantage of avoiding all 
pain to the animal, independently of rendering the experiment more easy. I find 
the action of ether perfectly harmless to life, not having observed a single death in 
consequence of its action, even where it had been prolonged for several hours. A 
curious anomaly exists with regard to the full-grown female frogs ; for I find in my 
experiments this winter that they are brought under its influence with much greater 
difficulty than the males and smaller animals, so much so, that after two hours’ expo- 
sure they are less influenced than one of the latter after five minutes. The advan- 
tages of ether are so great that I have abandoned my former method, to which I shall 
only recur when I have to describe the difference in microscopic appearances in 
animals that have been etherized from those which have not. 
