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Art. XXI. — Description an Appaj'utus for Restoring the 
Actiofi of the Lungs. By Mr Johk Mueray, Lecturer on 
- ' Chemistry. Communicated by the Author. 
JEvERY person -who knows the fine movements of the lungs, 
and their beautiful isochronism, will wonder that the can 
in any case be efficient in restoring their action. The pressure on 
the. chest, in the ex- pulsion of the air injected by this machine, is 
as rude and unequal as the action of the bellows itself is variable, 
directed, as it often is, by the error and. caprice of aii unskilful 
hand ; and even the forces will at all times be balanced with diffi- 
culty by the best directed efforts of the most dexterous operators. 
We have only to look at those numerous unsuccessful cases, 
which appeared so promising, to draw the painful conclusion, 
that the instrument commonly used, is quite unfit for the pur- 
pose, and that there still is a valuable desideratum to be accom- 
plished. 
Impressed with the magnitude of the subject, i have drawn 
up the following description of an apparatus, which seems cal- 
culated to supply the defect ; and I am happy to say, that it 
has met with the decided approbation of such medical gentle- 
men and mechanists as I have explained it to. 
Description of S. LIL 
A, is a cylinder, in which the piston-rod moves, having a solid 
piston, and passing at top through a close collar of leather. 
B, the piston-rod. 
C, represents a cylinder of tiuj with a partition concentric with 
it, which partition receives water (at o) heated to 98° Eahr. 
(the animal temperature), et infra^ and of course raises the 
air within the canister to the same temperature. 5, is a ca- 
nal and stop-cock connecting the air cylinder with the pump, 
and becoming the medium of supply. When asphyxia is 
occasioned by carbonic acid gas, a few drops of ammonia in 
the air-cylinder will be eminently serviceable, in the first 
instance ; for unless this air be abstracted or neutralized, 
we shall endeavour in vain to excite the suspended ener- 
