- ? 
466 Physiology and Practice of Medicine, 
proceeds from this point: in fact, respiration is no longer per- 
formed when’ these nerves only are divided, without injury to 
other parts, and the animal dies from asphyxia, accompanied by 
some peculiarities which M. Le Gallois has noticed. 
We are told that the total removal of the medulla oblongata 
im a rabbit, decapitated and revived, instantly kills it. If the 
same operation be performed on one which has not been so cir- 
" eumstanced, and in which the brain is perfect, it dies, although 
not in the same manner; the trunk of the body is instantly, 
deprived of life; but the head continues to live a short time, 
and is proved by a gaping (ai/lement) indicative of efforts made 
by the animal to carry on the function of respiration. 
If a rabbit be divided transversely into two equal portions, 
each of these continues to live separately during a certain time, 
which. is shorter or longer according to the age of the animal ; 
and longer the younger it is. ach of these parts feels and acts 
by itself: and they also die separately as soon as their respective 
portions of spinal marrow are destroyed. From this ‘view of 
the subject, it is evident there are two centres of vitality, or 
rather two sources of distinct sensations, The life of the whole 
trunk depends on the spinal marrow, and the life of each por- 
tion of the trunk on the portion ef spinal marrow which gives 
off nerves to it: besides, it so completely and entirely depends 
on this cause, that after the heart, liver, intestines, and internal 
organs of the animal have been removed, it continues to survive 
as long as the portion of spinal marrow which animates it is 
left entire. — 
Since it is not possible to remove the whole of the head of a 
warm-blooded animal, and leave the medulla oblongata in con- 
. tinuity with the spinal marrow, without dividing many con- 
siderable blood-vessels, the loss of blood from which greatly 
lowers vitality, experiments were made on some cold-blooded 
animals, such as salamanders. The wound caused by decapi- 
‘ tation cicatrised. and they continued to exist until life was ex- 
hausted by simple want of nutrition. : i 
These united: experiments prove that the maintenance of 
life in any part of an animal essentially depends on two cireum- 
stances; one of which is the integrity of that portion of the 
‘spinal marrow corresponding with the part; the other, the 
continuance of the circulation of arterial blood in this part, an 
effect produced by respiration: it follows then, that any portion 
of an animal can be made to exist separately (?solément) so long 
as both these conditions can be fulfilled. 
M. Le Gallois supposes that the brain wills and regulates all 
the animal motions, but the movements themselyes depend on 
the influence of the spinal marrow. . A cold-blooded animal, for 
example, 
