276 BACTERIOLOGY. 



agar and bouillon should be placed on the table. A num- 

 ber of clean cover-glasses (p. 140), or glass slides should 

 also be available. 



The animal should be nailed or tacked to a board. This should be 

 about 34 cm. wide and 54 cm. long-. It is well to surround it with a 

 raised border, and to fill any crack that may be present with melted 

 paraffin. The board, thus prepared, will not leak and hence can be 

 thoroughly disinfected after use. Instead of a board, a galvanized 

 iron or zinc tray can be used. In the latter case the animal is fast- 

 ened by means of strings tied to the leg's and slipped through holes 

 on the side. 



The animal is placed on its back, on the board or tray, 

 and its feet, extended as much as possible, are fastened 

 with nails or cord as the case may be. The hair over the 

 abdomen and thorax is thoroughly moistened with a cloth 

 soaked in mercuric chloride. With a pair of sterilized 

 forceps, the skin over the lower part of the abdomen is 

 raised and a slight transverse nick is made with sterilized 

 scissors. Into the opening thus made, the lower blade of 

 the scissors is introduced and an incision is made along the 

 median line to the neck. While making the incision, the 

 skin is kept raised by means of the forceps to avoid cutting 

 through the abdominal or thoracic walls. At each end of 

 this incision, lateral cuts are made in the direction of the 

 extremities and the two flaps of skin, thus prepared, are 

 carefully reflected, thus exposing the entire abdominal and 

 thoracic walls. The condition of the subcutaneous tissue, 

 of the abdominal walls, of the blood-vessels and the 

 presence or absence of pus, edema, gas, etc., should be 

 noted. 



Before proceeding further, it is well to prepare several 

 cover- glasses from the subcutaneous tissue. The cover-glass 

 is placed on the desired spot. It is then seized at the edge, 

 by the forceps, and carefully drawn off, not lifted up. If 

 much edematous fluid is present it will be better to take 

 up some of this on a looped wire and then spread it over 



