INTO THE VEINS OF LIVING ANIMALS. 
251 
accelerated, the testes descended into the scrotum, the pulse be¬ 
gan to be developed, and the horse was covered with perspiration. 
I then proposed to let him rise, which he did in a moment. He 
was led on to his stable ; the sweat by degrees dried away, and 
an hour afterwards it was difficult to perceive that any thing had 
ailed him.’* 
Such are the only three cases that have occurred in veterinary 
practice of accidents happening from the accidental introduction 
of air into the veins in surgical operations. In human surgery, 
however, these cases have been much more numerous. They 
have amounted to more than 30. Our space does not permit us 
to give a detailed history of any of these cases, and we will only 
say that, during some surgical operations on the superior part of 
the chest, and in the neighbourhood of large venous trunks, this 
introduction of air into the veins has occurred. It has always 
been accompanied by a kind of gurgling or of hissing, as when the 
air is admitted in small quantities into the cavity of an exhausted 
receiver, or, according to others, more resembling the sound when 
air is rushing through a small aperture in the chest of a living 
animal. We will add, that in every case, at the close of this noise, 
evidently occasioned by the rushing of air into the vein, some 
fearful symptoms have followed, such as plaintive cries, syncope, 
distortion of the eyes, extreme paleness, imperceptible pulse, sus¬ 
pended respiration, and that the succession of these symptoms 
has been strangely rapid, and the death sudden. 
Surprised at these remarkable phenomena, produced by the pe¬ 
netration of air into the circulatory vessels, physiologists have en¬ 
gaged in various experiments, w ith a view to discover the mode of 
action of this fluid on the living tissue, and the organs which are 
so strangely affected by it. Treading in nearly the same path, the 
different experimentalists have arrived at strangely different con¬ 
clusions. 
Bichat, in his treatise On Life and Death,” maintains that the 
air introduced into the venous vessels destroys the functions 
of life by its direct action on the brain, and that the circulation is 
necessarily interrupted, because the cerebral influence is first 
suspended. 
Nysten, on the contrary, after numerous experiments made in 
1811 on this subject, arrived at the conclusion that the atmospheric 
air injected into the venous system of different animals, destroys 
them by causing an enormous distention of the pulmonary auricle 
and ventricle. When, however, a great quantity of air is intro¬ 
duced, the bronchial passages are embarrassed by its presence, 
and thence results cough, spumy expectoration, guttural breath¬ 
ing, death, and altered structure of the lungs. 
