180 Remarks on the Apparatus 
example does not fall under the rule of subtraction; and hence 
the operations of algebraic addition cannot be ‘‘ restricted”’ to 
quantities of like signs; neither can the operations of algebraic 
subtraction beso “ restricted ;”” hence a mixture of operations must 
inevitably take place under each rule: and hence it is fairly in- 
ferred, that the terms addition and subtraction are not sufficiently 
comprehensive in meaning to denote that mixture of operations 
confing under each of these rules. 
March 1822. Iam, sir, &c. 
W.X.Y. 
P.S. I have confined my remarks to the author’s first letter, 
because his second appears to carry its answer along with it. | 
XLI. Remarks on the Apparatus for restoring the Action of 
the Lungs. By Joun Murray, F.L.S. M.W.S., ce. &S'c. 
To Dr. Tilloch. 
Feb. 15, 1822. 
Sir, — You were good enough to admit into your pages some 
remarks of mine on the important subject of suspended anima- 
tion, accompanied with a sketch of my invention: a finished 
form of that apparatus, it has already been stated, was presented 
by me to the Royal Humane Society. ‘That invention embraced 
all the desiderata which, as far as occurred to my mind, could be 
accomplished by mechanical means, with provision for the occa- 
sional introduction of chemical agency. I founded my deductions 
on Dr. Carson’s very ingenious and beautiful description of the 
machinery of the lungs, and Messrs. Allen and Pepys’s accurate 
‘researches on respiration; and [ conjoined my own experiments 
on suspended animation with these. 
_ That I had “a single eye” to the cause | meant to serve, is 
an inference warranted by my own feelings, and one which will 
‘be fully sanctioned by those whe known me best. The simple 
approbation of the Royal Humane Society was the only return 
in expectancy. I would indignantly spurn every other considera- 
tion in what I conceive to be an imperative duty. 
The following is introduced, I am free to confess, with a view 
of bringing the question of suspended animation fairly before 
the public, and of soliciting objections (if there do exist any well- 
‘grounded counter opinions) to the apparatus which I have re- 
commended for restoring the action of the lungs. Having thrown 
down the gauntlet, I shall endeavour to answer these counter 
conclusions (provided always the antagonist be non- anonymous) 
with what skill I may: if worsted in the conflict, I trust I shall 
not be found to persist in error, , 
Con* 
