148 PURE CULTURES FROM PATHOLOGIC MATERIAL 



50 to 100 c.c. of a fluid culture medium. When everything is ready, 

 the syringe is taken out of the small instrument sterilizer or out of its 

 receptacle in which it has been sterilized. The point of the needle 

 is rapidly flamed and the needle is plunged into the animal's vein, 

 which has been previously compressed centrally just beyond the point 

 where the puncture is to be made. When the barrel of the syringe is 

 full of blood and the needle has been withdrawn, the culture flasks 

 are opened by an assistant and the blood transferred to them in the 

 proportion of 1 to 5 c.c. to 50 to 100 c.c. of the fluid culture medium. 

 The flasks are closed immediately, the cotton plugs flamed and the 

 receptacles placed in the incubator. After twenty-four hours some of 

 the contents of the flasks are poured into centrifuge tubes (carefully, 

 so as not to permit any contamination from the air). The tubes are 

 next centrifuged and cover-glasses, which are stained and examined 

 in the usual manner, are prepared from the sediment. If any organ- 

 isms are found, culture tubes with solid media are inoculated from the 

 fluid media. It is also advisable to pour plates (Petri dishes) to 

 detect contaminations if any are present. 



Inoculation from Postmortem Material. It often becomes necessary 

 to obtain pure cultures from postmortem material. If the animal 

 has not been dead long, or if immediately after death the body has 

 been placed on ice, the procedure is not at all difficult, and is as follows : 

 If the animal is a small one, not larger than a medium-sized dog, it 

 is best to place the cadaver on a board and stretch out the four legs 

 by fastening them with twine to four nails or blocks driven into the 

 four corners of the board. An incision from the sternum to the sym- 

 physis pubis is made with a sterile knife and the skin is loosened from 

 the thoracic and abdominal walls and tacked to the board. The peri- 

 toneum is then incised and the bony thoracic wall is removed by cutting 

 through the costal cartilages. This is all done with sterile instruments 

 which have been changed several times. When the heart is exposed 

 it is raised with a pair of sterile forceps and the wall of the right 

 ventricle is cut with sterile scissors or knife. As soon as the blood 

 flows out, culture tubes are inoculated with it, using the platinum loop. 

 Cultures may also be inoculated from the other organs with the aid 

 of a very strong platinum loop. This is heated, and while still hot is 

 pushed into the parenchyma of the organ, where it is left a few seconds 

 until cool and then pushed in a little farther and small bits of tissue 

 are withdrawn from the organ. With the particles so obtained culture 

 media are inoculated. The procedure differs somewhat with large 

 animals. The heart's blood is best obtained in the same manner, 

 but the other organs should be removed and placed upon a table. 

 A large flat knife is then heated over a flame and is pressed, while 

 quite hot, on the organ. This singes the surface. The spot so treated 

 is next cut into with a sterile knife and a platinum loop introduced 

 into the incision to obtain some juice for inoculating culture tubes or 

 pouring plates. 



