I 
between his results and my own scarcely any discrepancies which may not 
be justly considered as due to the fact that we employed different agents to 
bring about the desired end. As to these differences I shall presently have 
to say a few words before attacking the subject of this present essay ; but 
I should be ungracious were I not to seize the first occasion to thank Dr. 
Richardson for the courtesy with which he has seen fit to speak of my 
experiments, and for the generous care with which he has brought my results 
before an English audience. I may add, that without the aid of his own 
brilliant and useful method of causing local anaesthesia, I should have been 
unable to pursue this line of study at all. 
Dr. Richardson describes local anaesthesia where ether is used as pre¬ 
senting the following phenomena :— 
First stage : Temperature 96° F. ; sensibility perfect. 
Second stage : Preaction ; removal of nerve-force ; increase of tempera¬ 
ture and of vascularity ; exalted sensibility. 
Third stage: Inertia; no nerve-force; temperature 16° F.; perfect 
insensibility; solidification of fluids of tissues; no blood. 
Fourth stage: Reaction; return of vascularity of paralyzed vessels ; 
increased vascularity and temperature; exalted sensibility; re-solution of 
fluids of tissue ; innervation continued. 
Fifth stage: Return to natural state. 
All of these stages probably exist in every case of freezing of the tissues 
in warm-blooded animals ; but when rhigolene is employed, the stage of 
preaction is so brief as almost to defy observation, owing to the great 
rapidity with which that fluid congeals the part. It differs also from ether 
in that it freezes less deeply. The former liquid chills so large and deep a 
layer of the cerebellum causes motion forward, and that deeper irritation produces 
retrogression. Is it not probable that the first slight chilling only reached the 
outer layers, and so gave rise to the forward motion, whilst the reaction after deep 
freezing, affecting a larger and less superficial mass of the organ, caused retro¬ 
gression. 
In another place Dr. R. seems to consider that retrogression, as I have men¬ 
tioned above, is due to temporary suspension of the cerebellar function. I myself 
have not seen this occurrence while the part was really frozen ; indeed, so sudden 
is the reaction, that you can scarcely be sure, a moment after releasing the bird, 
that reaction has not begun. On the other hand, it was clear to me that the time 
of greatest retrogressive movement was coincident with the period of profoundest 
reaction ; so that, whatever view we take, must accept a condition of cerebellar 
irritation as a part of the explanation of the backward tendencies. In corrobora¬ 
tion of these very hastily stated views, I may add, that ablation of the cerebellum 
does not produce those backward movements which can be obtained by irritation 
of limited regions of this ganglion ; and that the experiments of this present 
paper seem also to favour the view that, in enforced retrogression, forward motion 
or lateral movement, the principal element of their production is an irritation 
which affects some mass or masses of ganglionic matter so as to cause convulsive 
efforts which are vertiginous in character. 
