238 BACTERIOLOGY. 



tacks, towels, dishes, and all other implements used at 

 the autopsy, be sterilized by steam. All cultures, cover- 

 slips, and, indeed, all articles likely to have infectious 

 material upon them, must be sterilized as soon as they 

 are of no further service. 



What has been said with regard to the study of dead 

 tissues obtained at autopsy applies equally well to the 

 bacteriological study of tissues and exudates obtained 

 during life. In the latter case, however, certain pre- 

 cautions are always to be observed. In the first place, 

 it is desirable to obtain the materials under aseptic pre- 

 cautions, care being taken that no disinfectant fluids 

 are mixed with them. They should be subjected to 

 study as soon as possible after removal from the body. 

 In the case of tissues that cannot be examined on the 

 spot, they should be placed in a sterile Petri dish or 

 in a stoppered, sterile, wide-mouthed bottle and taken 

 at once to the laboratory. The surface should then be 

 seared with a hot knife and an incision through the 

 seared area into the centre made with a knife that has 

 been sterilized and allowed to cool. From the depths 

 of this incision enough material may be obtained for 

 microscopic examination and for the preparation of 

 cultures. Fluid exudates that must be taken to the 

 laboratory should be collected in either a sterile test- 

 tube, or, better, in a sterile capillary tube that is 

 subsequently sealed at both ends in a gas-flame. 

 When bacteriological examination of the blood dur- 

 ing life is required, it is customary to obtain the neces- 

 sary sample of blood by pricking the skin. It must 

 be remembered, in this connection, that the skin usu- 

 ally contains a number of species of bacteria that 



