INOCULATION OF ANIMALS 



121 



one end out to a fairly narrow point, plugging the tube with 

 glass wool above the point where the narrowing commences, and 

 sterilising by heat. By filtering an emulsion through such a 

 pipette, flocculi which might block the needle are removed. If 

 a solid organ or an old culture is used for inoculation it ought 

 to be rubbed up in a sterile porcelain or metal crucible with a 

 little sterile distilled water, by means of a sterile glass rod, and 

 the emulsion filtered as in the last case. 



The methods of inoculation generally used are : (1) by 

 scarification of the skin ; (2) by subcutaneous injection ; (3) by 

 intraperitoneal injection ; (4) by intravenous injection ; (5) by 

 injections into special regions, such as the anterior chamber of the 

 eye, the substance of the lung, etc. Of these (2) and (3) are 

 most frequently used. When an anaesthetic is to be administered, 

 this is conveniently done by placing the animal, along with a 

 piece of cotton-wool or sponge soaked in chloroform, under a 

 bell-jar or inverted glass beaker of suitable size. 



1. Scarification. A few parallel scratches are made in the 

 skin of the abdomen previously cleansed, just sufficiently deep 

 to draw blood, and the infective material is rubbed in with a 

 platinum eyelet. The disadvantage of this method is that the 

 inoculation is easily contaminated. The method is only 

 occasionally used. 



2. Subcutaneous Injection. A hypodermic syringe is charged 

 with the fluid to be inoculated. The hair is cut 



off the part to be inoculated, and the skin 

 purified with 1 to 1000 corrosive sublimate. 

 The skin is then pinched up and, the needle 

 being inserted, the requisite dose is administered. 

 The wound is then sealed with a little collodion. 



3. Intraperitoneal Injection. This may be 

 performed by means of a special form of needle. 

 The needle is curved, and has its opening not at 

 the point, but in the side in the middle of the 

 arch (Fig. 49). The hair over the lower part 

 of the abdomen is cut, and the skin purified with 

 an antiseptic. The whole thickness of the ab- 

 dominal walls is then pinched up by an assistant, 

 between the forefingers and thumbs of the two 

 hands. The needle is then plunged through 

 the fold thus formed. The result is that the 

 hole in the side of the needle is within the 



abdominal cavity, and the inoculation can thus be made. 

 Intraperitoneal inoculation can also be practised with an 



FIG. 49. Hollow 

 needle with 

 lateral aperture 

 (at a) for iutra- 

 peritoneal in- 

 oculations. 



