THe MIcROScOPE. 55 
more of acid may be added to the remainder of the glycerine, 
and mix as before. Lastly, mix the alcohol and water very 
gradually, shaking the bottle thoroughly after adding each suc- 
cessive portion till the whole is mixed. 
INJECTING KIDNEYS. 
_ Inject first the kidney of a pig or sheep, using the carmine 
gelatine mass. Try a second kidney with both the carmine and 
blue masses ; injecting the arteries red and the veins blue. 
INJECTING A FROG. 
Wrap the frog in a napkin to protect the tissues and kill by 
dashing with some force against the table. Introduce one blade 
of the scissors carefully beneath the sternum and cut it through 
the median line. Slit open the pericardium. Cut an opening 
in the ventricle. Do not wait long for the blood to escape but 
wash it away as it appears with water. Introduce the filled pipe 
of the syringe, and secure firmly in place by passing the thread 
around the heart substance and back over the pin on the nozzle: 
Just the end of the pipe only should be included for if thrust 
in too far, there is great danger of the point passing through 
the delicate coats of the vessel. Try Beale’s transparent Prus- 
sian blue. 
INJECTING A FISH. 
Cut off the tail of the fish and introduce the pipe of the 
syringe into the divided vessel situated just beneath the spinal 
column. The pipe need not be tied. Use the Prussian trans- 
parent blue. 
INJECTING A CAT. 
Cover with a large funnel and place a small sponge satu- 
rated with chloroform in the chamber with the animal. When 
thoroughly under the influence of the anzesthetic, remove to a 
board, place on the back and secure the extremities firmly with 
strong twine fastened to nails, previously driven in the board. 
Fasten the head firmly by a regular gag or by twine. Do not 
let the animal die yet ; keep administering the chloroform on a 
sponge held over the mouth as occasion requires. The usual 
method is to remove the sternum by cutting the intercostal 
cartilages on either side and injecting from the heart. To do 
