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velopment in London, where he slowly attained a respectable place 
as a physician. His contributions to the practice of his profession, 
both before and after he settled in London, were numerous, always 
ingenious, often original, generally valuable, but sometimes contro- 
vertible. Of all these contributions none perhaps will convey a 
higher idea of his acute and inventive discrimination as a physician, 
than his inquiry, begun in 1824, and perfected some years after- 
wards, into the constitutional effects of the loss of blood, of which he 
successfully investigated the phenomena, supplied the explanation, 
and detailed the conclusions, in the shape of valuable instruction, for 
distinguishing between inflammation and nervous irritation, thereby 
laying down the means of escape from fearful errors at that time 
often committed by the incautious and uncompromising admirers of 
blood-letting as a remedy. 
But the credit, which may be justly claimed for Marshall Hall 
for his contributions to medical experience and practice, sinks into 
insignificance when compared with his higher fame as a physiologist. 
It belongs properly to the sister Boyal Society to sketch biogra- 
phically the details of his discoveries in physiology. From me they 
can receive but a brief and passing notice, without too great a de- 
mand on your time and attention. I must confine myself, indeed, 
to only one of them, but that the greatest of all, the precursor and 
foundation of all the rest, and sufficient of itself to stamp Mar- 
shall Hall as an inventive genius, whose name will go down to 
posterity as one of the pillars of physiological science in the present 
century. 
It is evident from his works that Marshall Hall’s attention had 
been eagerly turned to the immortal discoveries of our greatest 
Scottish physiologist in these recent times, the late Sir Charles Bell, 
in regard to the functions of the brain, spinal marrow, and nerves. 
From that moment the nervous system was his great centre of attrac- 
tion. Sir Charles first sighted, and laid down in an undeniable 
shape, the grand fact in the physiology of the nervous system, that 
sensation is conveyed and motion governed by different nerves, or 
different filaments of nerves, having different origins in the cerebro- 
spinal system. Hall, however, was the first to see that this se- 
paration of what were once conceived to be common functions of 
all, or almost all, nerves, was not enough to account for the whole 
