GENERAL BACTERIOLOGICAL DIAGNOSIS 133 



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scopie examination of the material submitted ; (2) of an attempt 

 to isolate the organisms present ; and (3) of the identification of 

 the organisms isolated. We muet, however, before considering 

 these points, look at a matter often neglected by those who seek 

 a bacteriological opinion, namely, the proper methods of ob- 

 taining and transferring to theMbacteriologist the material which 

 he is to be asked to exo,mine. The general principles here are 



(1) that every precaution must be adopted to prevent the 

 material from being contaminated with extraneous organisms ; 



(2) that nothing be done which may kill any 

 organisms proper to the inquiry ; and (3) that 

 the bacteriologist obtain the material as soon 

 as possible after it has been removed from its 

 natural surroundings. 



Fluids from the body cavities, pus, urine, 

 etc., may be secured with sterile pipettes. 

 To make one of these, take 9 inches of 

 ordinary quill glass -tubing, draw out one 

 end to a capillary diameter, and place a little 

 plug of cotton wool in the other end. Insert 

 this tube through the cotton plug of an 

 ordinary test-tube, and sterilise by heat. To 

 use it, , remove test-tube plug with the quill 

 tube in its centre, suck up some of the fluid 

 into the latter, and replace in its former 

 position in the test-tube (Fig. 42). Another 

 method very convenient for transport is to 

 make two constrictions on the glass tube at 

 suitable distances, according to the amount 

 of fluid to be taken. The fluid is drawn 

 up into the part between the constrictions, 

 'but so as not to fill it completely. The 

 tube is then broken through at both con- 

 strictions, and the thin ends are sealed by heating in a flame. 



Solid organs to be examined should, if possible, be obtained 

 whole. They may be treated in one of two ways. (1) The 

 surface over one part about an inch broad is seared with a 

 cautery heated to dull red heat. All superficial organisms are 

 thus killed. An incision is made in this seared zone with a 

 sterile scalpel, and small quantities of the juice are removed by 

 a platinum spud to make cover-glass preparations and plate or 

 smear cultures. (2) An alternative method is as follows : The 

 surface is sterilised by soaking it well with 1 to 1000 cor- 

 rosive sublimate for half an hour. It is then dried, and the 



Fig. 42.— Test-tube 

 and pipette ar- 

 ranged for obtain- 

 ing fluids contain- 

 ing bacteria. 



