186 BACTERIOLOGY. 



is very dirty it may be scrubbed with soap and water. 

 Disinfection of the skin is impossible, so that it need 

 not be attempted. If the inoculation is to be by means- 

 of a hypodermatic syringe, then a fold of the skin may 

 be lifted up and the needle inserted in the way common 

 to this procedure. If a solid culture is to be inoculated, 

 a fold of the skin may be taken up with the forceps 

 and a pocket cut into it with scissors which have previ- 

 ously been sterilized. This pocket must be cut large 

 enough to admit the end of the needle without its 

 touching the sides of the opening as it is inserted. 

 Beneath the skin will be found the superficial and deep 

 connective-tissue fasciae. These must be taken up with 

 sterilized forceps, and with sterilized scissors incised in 

 a way corresponding to the opening in the skin. The 

 pocket is then to be held open with the forceps and the 

 substance to be inserted is introduced as far back under 

 the skin and fasciae as possible, care being taken not to 

 touch the edges of the wound if it can be avoided. The 

 M'ound may be then simply pulled together and allowed 

 to remain. No stitching or efforts at closing it are 

 necessary. 



During manipulation the animal must be held still. 

 For this purpose special forms of holders have been 

 devised, but if an assistant is to be obtained for the 

 operation, the simple subcutaneous inoculation may be 

 made without the aid of a mechanical holder. 



For mice, however, a holder is of much convenience. 

 This piece of apparatus consists of a bit of board of about 

 7 X 10 cm. and 2 cm. thick, upon which is tacked a hol- 

 low, tapering roll of wire gauze, a truncated cone of 

 about 6 cm. long and of about 1.5 cm. in diameter at 

 one end and 2 cm. at its other end. 



