The Microscope. 157 



the animal, and as it is but little more trouble, we will give the 

 method. Although only about one-thirteenth of the weight of an 

 animal is of blood, we will need a much greater proportion of in- 

 jecting fluid, because the arteries must be well distended with the 

 gelatine in order to fill the capillaries. I prefer a cat not more than 

 about one-third or one-half full size, because the specimens from 

 such make nicer microscopical slides, than larger ones do. 



For a full sized cat I pi ice two ounces of Seilei-'s injecting gelatine 

 into a wide-mouthed bottle with twenty ounces of cold water. After 

 soaking ten hours or more the gelatine will be soft, but the pieces 

 will retain their form until heated. The bottle is next placed in a dish 

 of hot water, and after the gelatine has dissolved it should be strained 

 through a cloth, placed in a bowl and be kept warm. 



We will now try the injecting syringe with warm water, to 

 make sure that it works well. 



Next see that we have at hand a box large enough to easily 

 admit the cat, also have a bottle of chloroform, a piece of cloth or a 

 small sponge, a couple of surgeon's curved needles threaded with 

 cotton or linen, (silk sticks to the wet hands, making it more difficult 

 to handle) a sharp pocket or other sharp-pointed knife, a pair of 

 scissors, a large wash basin with warm water, a pail of cold, or bet- 

 ter, ice water, and a kettle of hot water. 



We will now take up our cat, fondle it a little to prevent fright, 

 then lay it into the box and close the lid and place our foot on it, 

 next saturate the sponge or piece of cloth with chloroform, raise the 

 lid sufficiently to admit the anesthetic and slip it in. It is likely 

 that a paw will be protruded, but pressure on the lid will cause the 

 retraction of the foot. 



We can now sit or stand on the box until we feel no more signs 

 of movement from within. When the animal is well under the 

 chloroform, but not dead, we will remove it from the box, and, com- 

 mencing below the umbilicus, open the abdomen, run two fingers 

 over the intestines as guides, we cut between the fingers, from 

 within outward until we reach the neck. 



With the scissors we will cut away a portion of the ribs and 

 adhering muscle which are in the way of conveniently working at 

 the heart. Now we will cut off about one half -inch of the apex of 

 the heart, which will open the left ventricle only. 



To drain the blood from the animal, we will hold it up alter- 

 nately by the ears and tail, then place it in a basin of warm water. 



Now pass the detached nozzle of the injecting syringe up 

 through the open ventricle until its end is about onie quarter of an 



