INOCULATION OF ANIMALS. 



103 



ion. The substance in the cannula is forced out of it with a 

 stiff, sterile, platinum wire. (Fig. 37.) 



The peritoneal cavity may be inoculated 

 through an incision in the abdominal wall, into 

 which the desired substance may be introduced 

 with a sterile platinum wire, the incision being 

 closed with sutures. 



But a more convenient method in many cases, 

 both for subcutaneous as well as intraperitoneal 

 inoculations, is the use of a hypodermatic syringe. 

 Material from the surface of solid media can be 

 suspended in sterile beef-broth or physiological 

 salt solution, or tissue pulp may be mascerated 

 in the same liquids, or cultures in fluid media 

 used directly for these injections. 



Intravenous inoculation is most commonly 

 practiced upon rabbits. A small vein which is 

 near the posterior margin of the ear of the rabbit 

 is easily reached from the dorsal surface ; the ear 

 having been shaved and washed with alcohol, 

 the hypodermatic needle is introduced directly 

 into this vein. In making a hypodermatic injec- 

 tion, the needle and syringe should of course be 

 sterilized before and after each operation. 



For the inoculation of mice resort may be had 

 to some sort of mouse-holder (Fig. 34), or the 

 animal may be held by an assistant, who takes 

 the skin at the back of the neck between his 

 fingers and at the same time holds the tail. 

 Resort may be had to etherization by using a 

 few drops of the anesthetic on a bit of cotton 

 wool placed in the jar with the mouse, but there 

 is danger of killing the animal in this way. After 

 inoculation the mice may be kept in a glass jar covered with 



Fig. 37. 



