202 BACTERIOLOGY. 



screw, with which the apparatus (Fig. 40) is provided. 

 The animal usually remains perfectly quiet and may be 

 handled without difficulty. 



FIG. 40. 



Mouse-holder, with mouse in proper position. 



The hair from over the root of the tail is to be care- 

 fully cut away with the scissors, and a pocket cut 

 through the skin at this point. The inoculation is then 

 made into the loose tissue under the skin over this part 

 of the back in the way that has just been described. It 

 is best always to insert the needle some distance along 

 the spinal column, and thus deposit the material as far 

 from the surface-wound as possible. 



As the subcutaneous operation is very simple and 

 takes only a few moments, guinea-pigs, rabbits, and 

 pigeons may be held by an assistant. The front legs 

 in the one hand and the hind legs in the other, with 

 the animal stretched upon its back on a table, is the 

 usual position for the operation when practised upon 

 guinea-pigs and rabbits. The point at which the inoc- 

 ulations are commonly made is in the abdominal walls 

 either to the right or left of the median line and about 

 3 cm. distant. When pigeons are used they are held 

 with the legs, tail, and. ends of the wings in the one 

 hand, and the head and anterior portion of the body 



