620 
DE. A. GAMG-EE ON THE ACTION OE NITEITES ON BLOOD. 
1 metre pressure), whilst 100 cub. centims. of the same blood after the addition of nitrite 
of amyl yielded only 2-87 cub. centims. 
These experiments, therefore, bear out, in a striking and satisfactory manner the 
results of those in which carbonic oxide was made to act upon blood which had been 
treated with nitrites. 
The latter experiments showed that carbonic oxide had lost its power of thrusting out 
oxygen, although from certain facts which had been previously described, it appeared 
that the oxygen of the blood is neither expelled nor permanently taken possession of 
by nitrites. 
The fact that the loose oxygen which can be thrust out by CO is identical with the 
oxygen which is given up by blood in vacuo, led me to suppose that bodies which, as 
nitrites, have the power of locking up the loose oxygen of haemoglobin and preventing 
its expulsion by CO, would likewise prevent its removal by the air-pump. The hypo- 
thesis has proved to be a correct one. 
I must now make a few remarks upon the use of Sprengel’s mercurial aspirator in 
the extraction of the gases of the blood. 
In the detailed account of the individual experiments I have shown that, using the 
arrangement which I have employed, the removal of gases may be completed in a very 
short time (twenty-five or thirty minutes), and that the amount of gases obtained agrees 
admirably with the most successful of Pfluger’s analyses. Hitherto it has only been 
by Pfluger’s method (with the so-called dry vacuum) that the gases could be rapidly 
and completely removed from the blood ; and as the excellence of the method has been 
supposed to depend upon the removal of the vapour of water by the acid in the drying 
chamber, it appears to be worth while examining how it is that as good results can 
be obtained with the arrangement which I have employed. The object of the drying 
chamber containing sulphuric acid, in Pfluger’s method, is to make the vacuum as perfect 
as possible by removing the steam as well as the air. It is thus intended to obviate the 
influence which the tension of the vapour of water would have in causing the gases to 
be retained. It appears to me, however, that whilst the blood is still in ebullition it 
would be quite hopeless to try to obtain a dry vacuum, as simultaneously with the 
drying of the air by the action of the sulphuric acid, it would again become saturated 
with the vapour of water given off by the blood, so that whilst the sulphuric acid pro- 
bably hastened the evaporation it would scarcely influence the tension of the steam. 
The sulphuric acid would, however, tend to establish a continued current of steam 
from the receptacle in which the blood is boiled to the chamber containing sulphuric 
acid, and probably this current aids very much in sweeping out the gases from the blood. 
When Sprengel’s apparatus is used, all the apparatus connected with the blood-receiver 
is thoroughly and rapidly swept by a continual current of steam, and to this probably some 
of its efficacy in removing the gases of the blood may be referred. Probably it is this 
current which is the cause of the superiority of Pfluger’s arrangement, and of my 
adaptation of Sprengel’s apparatus, over the other methods which have been employed. 
