DE. A. GAMGrEE ON THE ACTION OF NITRITES ON BLOOD. 
611 
loose oxygen ; this gas, whose action on normal blood is so powerful, has for the time 
lost all power of action. It has also been shown that although CO loses its property of 
acting upon* blood treated with nitrites, it acquires it again if the blood be, subsequently 
to the action of nitrites, acted upon by sulphide of ammonium. 
It now remains for me to consider, before passing to the next series of experiments, 
whether nitrites have any action upon blood treated with carbonic oxide. Without 
detailing all the experiments which I have performed to obtain information on this 
point, I may state that nitrites appear to have no power of acting upon CO-blood. 
Whenever blood had been well agitated with carbonic oxide so as to acquire the well- 
known florid character and to become irreducible, it was found to be totally unaffected 
by the addition of solution of nitrites. 
Experiments in which the Gases of the Blood are hoiled out in vacuo, their amount 
determined , and their composition ascertained. 
Magnus was the first experimenter who made use of a mercurial pump in order to 
obtain the gases of the blood 1 . Before his time several inquirers had attempted to 
discover the presence of dissolved gases in the blood, but their results were so contra- 
dictory that little reliance could be placed upon them. Thus whilst Sir Everard 
Home 2 had asserted that the blood evolves gases when placed in vacuo, Stevens 3 and 
Hoffmann 4 in this country, and Gmelin, Mitscherlich, and Tiedemann 5 in Germany had 
stated that they had arrived at a different result. The failure of these experimenters 
was undoubtedly due to the imperfection of their air-pumps ; for, as Magnus discovered, 
it is essential, in order to remove the gases which exist in a state of solution and loose 
chemical combination in blood, to place it in a very perfectly exhausted space. Working 
with his very ingenious arrangement, Magnus found that blood yielded in vacuo from 
about 7 to 10 volumes per cent, of mixed gases, which consisted of a mixture of 
carbonic acid, oxygen, and nitrogen. These numbers are extremely low when compared 
with those obtained by experimenters who have worked according to more recent and 
improved methods. After Magnus, Lothar Meyer determined the gases existing in the 
blood 6 7 . Instead of a mercurial pump, he made use of the well-known method devised 
by Bunsen for boiling out the gases of water". His plan of working enabled him to 
secure as good a vacuum as Magnus obtained, and to boil the blood in addition ; it is 
probably due to this that Meyer obtained much larger quantities of gases than Magnus. 
1 Poggendorff’s ‘ Annalen,’ 1837, p. 583, “ IJeber die im Blute entkaltenen Gase, Sauerstoff, Stickstoff, und 
Kohlensaiire.” 
2 The Croonian Lecture for 1817, Philosophical Transactions, 1818, p. 181. 
3 Observations on the Blood, by W. Stevens, London, 1832. 
4 London Medical Gazette, 1833. 
5 Poggendorff’s ‘ Annalen,’ xxxi. t. 289. 
B Die Gase des Blutes, “ Zeitschrift, f. rat. Med.” Bd. VIII. p. 257 (1857). 
7 Gasometry, &c., by Robert Bunsen. Edited by Dr. Roscoe, 1857, p. 16. 
