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XXVI. Expenmental Inquiries into the Chemical and other Phenomena of Mespiration, 
and their Modifications by various Physical agencies. By Edwaed Smith, 
LL.B. {Bond.), M.B.C.P., Corresponding Member of the Academie des Sciences et 
Lettres de Montpellier, and of the Natural History Society of Montreal, Assistant- 
Physician to the Hospital for Consumption, Brompton, &c. Communicated by Sir 
B. C. Brodie, Bart., Pres. B.S. 
Eeceived December 16, 1858,— Eead January 20, 1859. 
XOTWITHSTAHDIHG the number of valuable observations upon this subject which have 
been made since the publication of the fii'st memoir of Lavoisier, there is but little 
which has been conclusively established. Of the causes inducing this, two have para- 
mount importance, VIZ. the practice of deducing large from small quantities, in reference 
to a subject which the quantities are ever varying, and the absence of any method 
whereby experiments could be repeated so frequently as to trace the changes actually 
procee^g during the inquhy. I have named these two because it is to correct them 
that I have directed my own observations. 
Dunng the past year I had the honour- to transmit to the Eoyal Society the results of 
an extended inquiry into the influence of various agents over the quantity of air inspired 
a short abstract of which was published in the ‘ Proceedings ’ of the Society. Since that 
period 1 have carried the inquiry further, and have determined the influence of those 
agents over the carbonic acid exhaled, as well as over other phenomena of respiration. 
The apparatus employed by previous observers for the determination of the quantity of 
carbonic acid contained in the expired ah, has been one of the following description •— 
1st. That adopted by Prout*, CoATHUPEf, VierordtJ, and Boeker§, consisting of a 
ag or other vessel of known capacity, into which the ah was exphed during a certain 
tune, and with a noted number of exphations; and a graduated tube, into which a por- 
tion of this expired air was passed, and the carbonic acid abstracted by potass, soda, or 
ime. This was adapted to experiments lasting a few seconds only at a time. 
2nd. A box of sufficient capacity to permit a man to be seated in it, and rendered air- 
tight, except at points which permitted the entrance and exit of air in given directions, 
ihe analysis of the exphed air was made by the aid of potass. This was ScHARLmG’sll 
meffiod, and by it he collected the products of the lungs and skin together, during a 
period not exceeding li hour. It was not practicable to determine the quantity of air 
Thomson s Annals of Philosophy, vols. ii. and iv. 
t Physiologic des Athmens, &c. 
II Annales de Chimie, vol. viii. p. 478. 
t Philosophical Magazine, 1839. 
§ Beitriige zur Heilkunde, &c., 1849. 
MDCCCLIX. 
4 X 
