ON THE MORBID STATES DENOMINATED PNEUMATOSES. 105 
us, that the blood flowing through this system is most greedy of 
it. Magnus, the Berlin chemist, has established, by his re- 
searches, that the blood has the power of dissolving a certain 
quantity of all gases in contact with it ; but that, whenever this 
liquid, already charged with gas, comes to absorb another, it 
can only do so by giving out a certain portion of the one first 
taken up; so that, when venous blood is agitated with hydro- 
gen, a portion of this gas is dissolved, and a corresponding 
quantity of carbonic acid already existing in the liquid is dis- 
engaged ; and when, instead of hydrogen, oxygen is made use 
of, an analogous result is obtained. The venous blood absorbs 
a certain quantity of gas, and liberates a quantity of carbonic 
acid nearly equivalent thereto. 
Persons engaged in dissection know full well that it is by no 
means an uncommon thing to meet with gaseous globules in the 
veins of animals slaughtered in a state of health. 
We also know that the insufflation of air into the jugular 
vein of a horse does not always produce ill consequences, much 
less death. Under these circumstances, without doubt, the air 
introduced becomes absorbed by the blood. 
Is gas likewise present in arterial blood 1 Chemists think 
so, and M. Lassingen assures us positively of the fact. Accord- 
ing to him, arterial blood, though in less quantity than venous 
blood, both contains acid gas and azote. 
Brummer has proved the existence of gas in arteries by the 
following experiment. After having produced a slow circula- 
tion by means of foxglove on a dog, he seized the aorta, and by 
means of a couple of ligatures dammed up the blood flowing 
through it, closing the farther ligature first, instantly after the 
contraction of the ventricle. On opening after a little while 
this imprisoned portion of trunk, he discovered an aeriform fluid 
in it, of which we shall anon ascertain the composition. 
We are told that every time we take a large quantity of 
blood away from an animal, we find gas in the arteries, intro- 
duced there to fill the void left by the flow of blood ; a void 
which is not suffered to pervade the arterial parietes, on account 
of their not returning with sufficient rapidity to their natural 
caliber. 
For a very long time it has been known that, after death, 
aeriform fluids occupy the place of the blood in the arteries, 
which has been propelled into the venous system. It was, 
indeed, from this discovery of Erudistratus that the arteries re- 
ceived the name they bear to this day. 
The presence of gases in the sanguiferous system, and in 
the interstices of tissues, is never observed, according to M. de 
Blainville, in the foetus, before it has respired. He assures us 
