238 BACTERIOLOGY 



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 sterilization 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 

 therefore, 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 extend- 

 ing from the point of the sternum to the genitalia is to be 

 made without touching the internal viscera. 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 scorched tracks on either side of the thorax. After 

 this the whole anterior wall of the thorax may easily be 

 lifted up, and by severing the connections with the dia- 

 phragm it may be completely removed. When this is done 



