a 
Pare 
MICROSCOPY. 239 
leased by Samuel Keehler about three miles from the village of 
Kutztown, who intends to have ready accommodations for visitors 
and explorers during this April.— H. W. Hoxtiensusn. Reading, 
Pennsylvania. 
MICROSCOPY. 
AN Improvep Mope or OBSERVING CAPILLARY CIRCULATION. 
As I have never seen in print the following method of exhibiting the 
circulation of the blood in the frog, I send it hoping that it may 
enable some one interested in such studies to demonstrate the 
distribution and influence of the nerves upon the capillary vessels 
and circulation. I have, for over twenty years, been aware of the 
peculiar manipulation presently to be described; where I first ob- 
tained the knowledge, or how, I cannot state. I have made the facts 
_ known to a great many microscopists, and have not, as yet, met 
any one who previously knew it. If we grasp a frog in the hand 
and plunge it in water about as warm as can be conveniently 
borne, say about 120°, though I have never measured this, judg- 
mg simply from the apparent warmth to the hand, we shall find 
that, in a few moments, the frog will become perfectly rigid ; it 
may now be removed and laid apon a plate for dissection. Care- 
fully Opening and stretching the parts by pulling upon the fore 
limbs gently, or even cutting the bones if necessary, the heart 
may be displayed, showing the contraction and expansion beauti- 
fully ; and if now the animal is placed in warm water, the lungs 
will immediately float out, and by a suitably contrived stage, the 
arculation may be examined. It is better, however, not to do this 
but to draw out gently the large intestine by means of blunt 
forceps, and then spreading the mesentery on the glass of the 
frog plate (I find it convenient to use a large one with an elevated 
S'ass, instead of one in the same plane, on which to spread the 
mesentery) we can observe the capillary circulation very nicely 
with 27 or Linch objective, by dropping a bit of thin glass over 
the place or with a higher power “immersion.” Of course the 
Parts opened must. be kept moist and covered with a cloth, and a 
few drops of tepid water added from time to time. If the experi- 
“ent has been properly conducted, the animal will remain per- 
the circulation will continue for hours; I cannot 
po ong, for I have never known it to cease until long after 
eS“ nished all the exhibition I have ever had occasion to make. 
Say how J 
