EXAMINATION FOR SPECIAL MICRO-ORGANISMS 



67 



withdrawing the plug of one of the tubes of serum 

 with the usual precautions, carrj' the end of the needle 

 down to the bottom of the tube. Placing it upon the 

 lowest portion of the medium withdraw the needle 

 gently, making at the same time with it a series 

 of transverse zig-zag lines across from side to side of 

 the medium. 



2. Replace the plug in the first tube, and, opening 

 the second, proceed in the same manner without re- 

 charging the needle. 



3. Carry out the same operation with the third 

 tube, again without charging the needle. 



4. Incubate at 37° C. 



In the course of the above operations it will be 

 found that the needle gradually becomes freed from 

 the organisms with which it was charged. In the 

 first tube a large number of colonies, most of them 

 confluent, will be found to develop, but the colonies 

 will become rarer and more isolated upon the 

 serum of the second and third tube. It is upon 

 either one or other of these two tubes that the 

 various colonies will be found suflficiently isolated for 

 examination. 



Methods of Examination for Special 

 Micro-Organisms in Milk 



Bacillus pseudo-tuberculosis of Pfeiflfer {found 



in London milk by Kleiti) — 



By the centrifuge or by sedimentation in an ice 

 chest for twenty-four hours obtain the particulate 

 matter of the milk to be examined. Inoculate 2 c.c 

 into a guinea-pig subcutaneously or intraperitoneally. 

 In the course of three to four weeks caseo-purulent 

 nodules will occur in the inguinal glands (if sub- 

 cutaneously inoculated), or in the omentum and pan- 

 creas and other organs (if intraperitoneally). Cultures 

 may be obtained best from glands, spleen, pancreas, 

 or liver. Examine the nodules by staining and 

 culture. They will have the following characters if 

 the disease be pseudo-tuberculosis : {a) Absence of 



^.1 



