28 
PROCEEDINGS OF THE ACADEMY OP 
[Biolog. 
Dr. Mitchell's experiments seem to him to justify the following conclu- 
sions : — 
1st. That the hearts of the frog and turtle heat much less rapidly in vacuo, 
and sometimes cease to act until the air is readmitted. That the vacuum 
most probably retards the heart's action by the mechanical effects it induces, 
as well as by depriving it of oxygen, since the beat in vacuo is long and la- 
bored, and the accelerating influence of the readmitted atmosphere is almost 
instantaneous. 
2d. That mere isolation from the air, as by placing the heart in oil, does 
not alter the rate of the heart's movements for some time, but lessens their 
ultimate duration. 
3d. That water, at serial temperatures, stimulates the heart, and very soon 
causes it to cease to pulsate. That water at higher temperatures, as 100° F., — 
113° F., produces much more rapidly the same results. 
4th. That glycerine, at serial temperatures, affects the heart but little, except 
as shortening the time during which it continues to pulsate. That glycerine 
at 32° F., depresses the heart's action, lessening the number of pulses per 
minute at least one half, and soon checking its movements altogether. That 
olive oil at 32S F., affected the heart very little at first, as to the number of 
beats per minute, but soon rendered them feeble, and finally stopped them ; 
though at the close of a longer interval than was required by glycerine at the 
same temperature.* 
5th. That when the heart has ceased to respond to one stimulus, however 
violent, it will usually remain sensitive to others, apparently far less power- 
ful. 
Dr. Leidy exhibited specimens of true bone, found in the kidney of a mink. 
It was situated in the fibrous tissue of the organ, the glandular substance 
of which was wasted away, its place being occupied by an enormous parasite, 
the Strongylus gigas. 
I5r. Woodward stated that he had found tubercular deposits upon the pleura 
of an opossum, which had been kept in confinement in the Academy for 
some time. 
Dr. Hartshorne, from the Committee appointed to devise and report upon 
a plan for securing a wide circulation of the Memoirs of the Department among 
medical readers, reported certain resolutions, which were read for the first 
time. 
This Report was adopted. 
A resolution was offered by Dr. Hartshorne, providing for the appointment 
of a Committee on Statistics, which was adopted. 
The following persons were duly elected members of the Biological Depart- 
ment :— W. M. Uhler, M. D., Prof. J. H. B. McClellan, M. D., Prof. Joseph 
Carson, M. D., Prof. J, Jones, M. D., Mr. Wm. S. Vaux, T. B, Wilson, M. D., 
Prof. H. F. Campbell, M. D., and William Hunt, M. D. 
* The glycerine was thinner than the English Glycerine, (Prick's), now in use, and 
altogether was a much less reliable article. For this reason I do not entirely trust the 
results observed when using glycerine. 
[Dec. 
