SUBCUTANEOUS INOCULATION OF ANIMALS. 211 



at the edge of the board. The mouse is taken up by 

 the tail by means of a pair of tongs and allowed to 

 crawl into the smaller end of this wire cone. When 

 so far in that only the root of the tail projects the 

 animal is then fixed in this position by a clamp and 

 thumb-screw, with which the apparatus (Fig. 45) is 

 provided. The animal usually remains perfectly quiet 

 and may be handled without difficulty. 



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 always best 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 inoculations 

 are commonly made is in the abdominal wall 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 in the other, 

 leaving the area occupied by the pectoral muscles, over 

 which the inoculation is to be made, free for manipu- 

 lation. The hair over the point selected for the in- 

 oculation should be closely cut with the scissors in 

 the case of guinea-pigs and rabbits, and from a small 



