MATERIAL FOR BACTERIOLOGICAL STUDY IOI 



be not confused by the addition of bacteria from the surface of 

 the body, from instruments or from the air during the collection^ 

 and transportation to the laboratory. Unfortunately the 

 laboratory study of such material is too often rendered untrust- 

 worthy or worthless through lack of attention to this point. 



When merely microscopic examination is to be undertaken, 

 contamination may not be serious, and an antiseptic, such as 

 two per cent of carbolic acid, may be added to the material, if 

 fluid, and if solid it may be immersed in ten per cent formalin. 

 The bottles used should be new and clean. Such material may 

 also be spread on microscopic slides or cover-glasses in a thin 

 layer, dried, fixed in the flame, and transported to the labora- 

 tory. This method is not always free from danger when the 

 material passes through several hands. Special precautions for 

 collecting material for microscopic examination will be considered 

 in discussing the specific pathogenic microbes. 



Specimens of sputum should be raised from the trachea, bron- 

 chi and lungs after previously cleansing the mouth. Sputum 

 should be received into a sterile wide-mouthed bottle, and stop- 

 pered with a sterilized cork. The exterior of the bottle should 

 then be carefully washed with 5 per cent carbolic acid. 



Urine should be collected by catheter with careful aseptic 

 technic, and should be received in a clean sterilized bottle. 



Blood and transudates are collected by the technic previously 

 described (page 95). Blood is drawn from the vein by means 

 of the Luer syringe and is quickly ejected into several flasks of 

 broth (150 to 250 c.c.) and into Petri dishes where it is mixed with 

 melted agar, (cooled to 50 C. ) before clotting takes place. 



Cerebro-spinal fluid is obtained by inserting a sterilized needle 

 (4 cm. long for children, 8-10 cm. long for adults, and with 

 lumen i mm.) a little to one side of the median line in the back, 

 so that it enters the spinal canal between the second and third, 

 or between the third and fourth, lumbar vertebrae. Aseptic 

 technic is essential. The fluid coming from the needle is 

 received in a sterile tube. 



