ON THE INTUODUCTION OF AIR 
(force aspirante). It is our colleague, M. Amussat, who first 
proved in the most precise way, and almost with mathematical 
demonstration, that when an opening sufficiently large is made 
in that part of one of the jugular veins in which the flux and 
reflux of the blood may be perceived, air constantly enters into 
the sanguineous system. This is a truth, or, rather, a physiolo¬ 
gical law, and henceforth the property of science. 
It is unnecessary to add, that air may enter the vascular sys¬ 
tem through an opening effected much higher up in the jugular 
vein, and also by any other vein in the neighbourhood of the 
heart, such as the subclavian and the axillary, when, from any 
cause, the parieties of these veins are separated or distended ; 
but this is not the place to insist, at any length, on the con¬ 
ditions favourable or unfavourable to the admission of air into 
the veins. 
II. The state of the vascular system in the animals into whose 
veins air has been admitted. 
Dogs. —In fifteen dogs that were opened immediately after air 
had been introduced into their veins, we found a greater or less 
quantity of air in the right cavities of the heart, and in the pul¬ 
monary artery. The distention of the right cavities with spu¬ 
mous blood is sometimes so great, that they are treble their 
natural size. This kind of meteriozation of the right cavities is 
of invariable occurrence. The left cavities—one case alone 
being excepted—did not contain any air, and their diminished 
size was strangely contrasted with the enormous dilatation of the 
right cavities. In the excepted case, the left cavities contained 
a few bubbles of air. 
The cranium of some of the dogs that had been placed in a 
vertical position being opened, some bubbles of air were found 
in the jugular vein, on the opposite side to that into which the 
incision had been made, and also in the facial and cerebral veins, 
and in the sinuses of the dura mater. 
In four dogs, that were not opened until between the fourth 
and tenth day after the introduction of the air, there was 
only one in which we did not find some air either in the 
heart or the bloodvessels. In that one, opened on the fourth 
day, the right cavities of the heart were flaccid and collapsed*. 
It may be proper to remark, that in the three other dogs were 
* This experiment accords with two that were made by Nysten, who, at 
the end of three days, did not find any bubbles of air in the veins of the 
dogs into which he had injected it; but on the eighth or tenth day, this gas¬ 
eous matter, so little soluble in the blood, may be found in various parts of 
the circulatory system. 
