660 PROGRESS OF VETERINARY SCIENCE AND ART. 
resting case, which I had always looked upon as one of im- 
pregnation of one of the horns of the uterus, that had pro- 
truded through the inguinal canal. 
With regard to physiological researches, Hering notices at 
length an essay by my friends Chauveau and Faivre of 
Lyons, that I had for some time wished to bring before my 
readers. It refers to the movements and sounds of the 
heart. Twenty-six horses, ten dogs, and one monkey, were 
experimented on. In order to avoid the pain and struggling 
the animals were pithed, and artificial respiration was kept 
up ; the action of the heart was observed by the removal of 
several ribs ; the experiments would last in this manner for 
two or three hours at a time. It results that the dilatation 
of the heart is simply due to relaxation of the fibres, and the 
walls become flaccid and collapse; the systole is an active 
effort attended by rigidity of the muscular tissue when the 
volume of both auricles and ventricles is diminished, and the 
apex of the heart turns from left to right, and from before 
backwards. The heart’s action may be divided into three 
periods: — the first when the auricles contract and the ven- 
tricles widen ; the second, when the ventricles contract and 
the auricles open ; and the third, is a period of general expan- 
sion or relaxation, when the cavities of the heart all fill. 
The contractions of the auricles drive the blood only feebly 
and in part into the ventricles, which by their closure propel 
it into the arteries ; a portion, however, remains in the 
ventricles. The column of fluid within the arteries holding 
expanded the semilunar valves causes the blood wave to 
recede against the heart, and this is so neutralized by the 
shortening of the organ that the apex of the heart remains 
immoveable, whereas the base itself approaches the apex. 
Whilst all this is going on, the arterial trunks elongate and 
curve, and this brings the base of the heart back to its former 
place, when the systole ceases. The sounds of the heart 
occur through the expansion and closing together of the tri- 
cuspid valves. (Hering appends a query to this remark.) 
The contraction of the auricles is almost entirely unattended 
with sound ; the first sound of the heart occurs as the 
ventricles contract ; and the second, on the contrary, begins 
with the period of repose, or general relaxation of the heart. 
The heart beat occurs through the contraction of the ven- 
tricles when they change in form, and thereby an impulse is 
given against the surrounding parts, especially the wall of 
the chest, with which the heart is continually in contact. — 
See Lyons Journal for 1855, p. 53 7. 
In an annual report for 1854, it was stated by Leisering 
