56 STUDY AND IDENTIFICATION OF BACTERIA 



The large ear vein of the rabbit is used for intravenous inoculation. This can be 

 made to stand out with either hot water or xylol. 



In intraperitoneal injections the animal is best held head down so that the intes- 

 tines gravitate downward. The shaven skin is pinched up and the needle inserted in 

 the median line. 



In certain cases infection is secured by feeding the material to the experimental 

 animal. The material may be mixed with the food or introduced into the stomach 

 by a tube. 



CULIURING MATERIAL OBTAINED AT BIOPSY OR AUTOPSY OF MAN OR 



ANIMALS 



It is customary to sear with a heated knife or spatula a spot on the 

 surface of the organ from which cultures are to be made. Then intro- 

 duce at this point a sterile platinum spud and inoculate tubes of culture 

 media. The platinum loop may be used where an incision is made 

 into the organ with a sterile knife. The ordinary platinum loop, how- 

 ever, bends too easily. 



A bacteriological capillary pipette is a good instrument for taking up material. 

 After some practice one can do good work with a rubber bulb capillary pipette, 

 especially in taking up blood from right heart or blood-vessels. When great pre- 

 caution is necessary, as in culturing a removed gland or organ, the piece of tissue 

 may be dropped into 5% formalin solution for a few minutes, then washed in sterile 

 salt solution; next placed in a sterile Petri dish and the material obtained from the 

 center. It may be dropped for a few seconds into boiling water to sterilize the 

 surface. When autopsying experimental animals it is well to dip the dead animal 

 into 3% tricresol solution before opening up the body. 



