EDITORIAL OBSERVATIONS. 
67 7 
or both at once, became annulled by the section of the nerve 
belonging to the organs where its terminating divisions are 
distributed—-and this could only be done by living proof. 
It was indispensable for this purpose to divide alternately 
the two branches, or rather the double root, by which the 
mixed nerves are connected with the spinal marrow, in order 
to obtain conviction that, according to the peculiar case, it 
may be either one or other of the currents which may 
be interrupted by the operation. It is to the vivisections 
made by Sir Charles Bell, confirmed by those of Magendie, 
Muller, Valentin, Longet, &c., that we owe this valuable 
conquest in physiology, so fruitful in therapeutical appli¬ 
cation, and I may add, so consolatory likewise, even from 
the peculiar point of view in which we ourselves are accus¬ 
tomed to view the subject. We owe to the experiments 
made by M. Brown-Sequard the definitive demonstration of 
another important fact—that of the extension of the roots 
to the nerves dependent on the spinal marrow, to which 
they correspond. Further researches, made by the same 
physiologist, have brought to light one more fact of equal im¬ 
portance—that of there being no need of a total separation 
of the spinal marrow to occasion the interruption of all per¬ 
ception through the encephalus of sensitivity—that is to say, 
for the abolition of pain—it being sufficient to attack the 
gray substance which occupies the centre of the marrow. 
It has been ascertained likewise, that this same gray sub¬ 
stance, although serving to transmit to the sensorium all sen¬ 
sitive impressions, remains in itself absolutely insensible to 
all direct excitement. 
A moment’s reflection on the influence of external excite¬ 
ment on the formation of our ideas, will enable us to com¬ 
prehend these simple indications, and we need not, therefore, 
enter into further details. We are compelled to refer to the 
numerous treatises on physiology, which have been written 
on the subject for the instruction of those to whom our ex¬ 
planation may not suffice. Here they would perceive at 
once how entirely the idea of the sufferings which have been 
compulsorily inflicted upon animals, often of the lowest 
order, upon reptiles, upon batrachians, vanishes before that 
of the greatness of the results obtained. They will here be¬ 
hold that, in these functions of the nervous system, in this 
laboratory of thought, where all was formerly darkness and 
mystery, an invaluable flood of light has been admitted 
through the practice of vivisection. 
But we wish, above all things, to call your attention to 
those of a nature calculated to dispel a widely disseminated 
