The Microscope. ?9 



with the lingers, peel back the skin till the sternal cartilages are 

 reached. Incise these from below upwards, turn back the sternum, 

 uncover the heart and draw it out. Invert the animal over a bucket, 

 grasp the heart lightly at the base, cut off the apex and allow the blood 

 to drain away. All this should be done quickly, in order that the 

 animal die from exsanguination rather than from chloroform narcosis. 

 It does not matter much if the animal happen to die before the 

 finish, as much blood can be drained off before coagulation sets in. 



When the hemorrhage has ceased, place the animal on its back 

 and prolong to the pubes the incision first made. 



Whilst the animal is cooling the time can be employed in mak- 

 ing " stretchers " for the reception of certain specimens. This is 

 done as follows: Take three or four pieces of hard wood about 1^ 

 inches long, f inch wide, and ^ an inch thick. On the long, upper 

 side cut a notch the entire width, h the depth, and to 4 of an inch of 

 either end of the block, in length. On the bottom, at one end, cut 

 Roman numerals for the purpose of identification. Procure small 

 pieces of lead, fiatten them and tack to the middle of the bottom. 

 These should be only large enough to sink the block in alcohol. 



Now remove and preserve the parts and organs of the animal in 

 this manner and order: (1) The lungs with the lower portion of- 

 trachea, and (2) the heart with several inches of aorta and vena 

 cava ; separate the heart from the vessels, open the cavities and cut 

 out two or three pieces 1 inch square from the walls. Divide the 

 vessels into pieces ^ inch in length, wash, by waving gently to and 

 fi'o in a vessel of water, and drop them, together with the heart por- 

 tions, into alcohol. The jar should now be labeled. If it is desired 

 to make more sure of the identity of different tissues in the same 

 bottle, a good plan is to run, by means of a needle, small pieces of 

 colored worsteds through the specimens. These, with the specimen to 

 which they are attached, can then be recorded in a book to be kept for 

 the purpose. The lung, to be satisf actoi'ily hardend, should be injected, 

 through the trachea, with Miiller's fluid and then suspended in a large 

 jar. Small specimens can be hardened to a considerable degree, 

 however, by cutting them in flat pieces, about | an inch thick and 

 placing in alcohol. Pieces of the trachea should be presei-ved along 

 with the lung. (3.) The liver and gall bladder. Cut out one inch 

 cubes from the liver, which should include the capsule on one side. 

 With scissors, slit up the gall bladder and preserve in alcohol. (4.) 

 The kidneys, specimens of which can be placed with the liver. (5.) 

 The mesentery. Separate the intestines, and the web-like mesentery 

 which binds them together will come into view. Search for the 

 pacinian corpuscles, which are to be found as white specks in the 



