1UN 4 19*2 
T 
[Extracted from the American Journal of the Medical Sciences for January, 1868.] 
ON THE 
PRODUCTION OF REFLEX SPASMS AND PARALYSIS IN BIRDS, BY THE 
APPLICATION OF COLD TO DEFINITE REGIONS OF THE SKIN. 
ByS. WEIR MITCHELL, M.D., 
MEMBER OF THE NATIONAL ACADEMY OF SCIENCES. 
In the January number of this Journal for 1861, I placed upon recor 1 
a series of novel researches concerning the influence of extreme cold upon 
the various central nervous organs. I considered my results as having a 
double value, first, because they introduced to physiology a new method of 
examining the nervous system; and, second, because I was enabled, 
through this means, to discover and investigate certain remarkable phe¬ 
nomena produced by chilling the spinal centres of birds. To these latter 
facts I desire again to call attention. 
On the 11th of May, 186$, Dr.B.W. Richardson, of London, who it seems 
had been occupied with precisely the same line of investigation as myself, 
published the first of a series of lectures, in which he repeated and thoroughly 
confirmed the results I had obtained, while, at the same time, he added 
very valuable details, and a clear and careful examination of the influence 
of extreme cold upon nerve trunks—a subject on which I had not touched. 
While differing from this gentleman as to some of the conclusions at which 
he arrives, especially concerning the function of the cerebellum, 1 I find 
1 The chief point on which I differ from my friend, Dr. Richardson, is in regard 
to the inferences he makes from his experiments and my own, as to the physio¬ 
logical balance of control between the cerebellum and the anterior ganglia of the 
brain. Accepting Magendie’s views that the corpus striatum is endowed with a 
constant backward-propelling energy, while in the cerebellum resides an opponent 
influence, he states that freezing the cerebellum gives over the pigeon to the 
governance of the corpus striatum, and so occasions retrogression ; the reverse 
occurrence following the abeyance of function in the anterior centre. I have 
always believed that these various phenomena of retrogression—lateral motion, 
mouvement cle manage, &c., were due to excitation of parts, and not to annihilation 
of function ; and this view is sustained by the fact that mere punctures, which 
do not destroy the centres, are competent to occasion the enforced motions. In 
freezing, Dr. R. observed that the first chilling (stage of preaction) of the cere¬ 
bellum often gave rise to forward motions. The reaction, after deeper freezing, to 
backward activity. Now Flourens has shown that irritation of the superficial 
