234 BACTERIOLOGY. 



then completed with the scissors. The whole of the 

 skin is now to be carefully dissected away, not only 

 from the abdomen and thorax, but from the axillary, 

 inguinal, and cervical regions, and the fore and hind 

 legs as well. It is then pinned flat upon the board 

 so as to keep it as far from the abdomen and thorax as 

 possible, for it is from the skin that the chances of 

 contamination are greatest. 



It now becomes necessary to proceed very carefully. 

 All incisions from this time on are to be made only 

 through surfaces that have been sterilized. The sterili- 

 zation is best accomplished by the use of a broad-bladed 

 table-knife that has been heated in a gas-flame. The 

 blade, made quite hot, is to be held upon the region of 

 the linea alba until the tissues of that region begin to 

 burn ; it is then held transversely to this line over about 

 the centre of the abdomen, thus making two sterilized 

 tracks, through which the abdomen may be opened by 

 a crucial incision. The sterilization thus accomplished 

 is, of course, directed only against organisms that may 

 have fallen upon the surface from without, and there- 

 fore it need not extend deep down through the tissues. 

 In the same way two burned lines may be made from 

 either extremity of the transverse line up to the top of 

 the thorax. 



With hot scissors the central longitudinal incision 

 extending from the point of the sternum to the geni- 

 talia is to be made without touching the internal vis- 

 cera. The abdominal wall must therefore be held up 

 during the operation with sterilized forceps or hooks. 

 The cross-incision is made in the same way. When 

 this is completed an incision through the ribs with a 

 pair of heavy, sterilized scissors is made along the 



