ON 
RESPIRATION 
AND 
ANIMAL HEAT. 
By JOHN DALTON. 
(Read March a1, 1806.) 
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Ir is not my design, in the present Essay, 
to give a history of early opinions respecting 
the uses of Respiration, and the causes of 
Animal Heat. I intend to confine my obser- 
vations to such authors as have written on 
these subjects within the last thirty years; a 
period in which so many discoveries respecting 
heat and elastic fluids have been made, as to 
enable modern physiologists to give a much 
more rational account of that important ani- 
mal function, Respiration, than their prede- 
cessors could do. 
Priestley and Scheele discovered that oxygen 
was consumed during respiration, or the quan- 
tity of oxygenous gas inhaled was greater 
than that exhaled. Black and Lavoisier found 
that a considerable portion of the air expired 
