9$ BACTERIOLOGY. 



through the ribs on either side of the sternum with 

 sterilised scissors, and turning the sternum up 

 where it will be out of the way. The pericardium 

 is then opened, and the right auricle or ventricle 

 pierced with the point of a sterilised scalpel, and 

 inoculations and cover-glass-preparations are made 

 from the blood which escapes. 



The lungs also require to be especially studied. 

 They should be incised with a sterilised scalpel, 

 and inoculations and cover-glass-preparations made 

 from the cut surface. It may be necessary to 

 imbed a piece of lung or fragment of spleen, so 

 that it shall be free from air. This may be done 

 by isolating a fragment with the precautions just de- 

 scribed and depositing it upon the surface of a test- 

 tube of nutrient agar-agar. The contents of another 

 tube, which have been liquefied, and allowed to 

 cool almost to the point of gelatinisation, must then 

 be poured over it. From a potato a little cube 

 must be cut, the tissue deposited in the trough 

 thus formed, and the cube replaced. Blood may 

 also be taken directly from a vein by laying it bare 

 by dissection, making a small section with sterilised 

 scissors, and inserting an ose, the needle of a 

 Pravaz' syringe, a capillary tube, or the extremity 

 of the capillary neck of a Sternberg's bulb. If the 

 cultivation is contaminated by the presence of 

 putrefactive or other micro-organisms they must be 

 isolated subsequently by carrying out a series of 

 plate-cultivations. 



