METHODS OF INOCULATION 



145 



FIG. 47. -Hollow 

 needle with 

 lateral aperture 

 (at a) for hitra- 

 peritoneal in- 

 oculations. 



through the abdominal fold, it is partially withdrawn till the 

 point is felt to be free in the peritoneal cavity, when the injection 

 is made. There is little risk of injuring the intestines by either 

 method. 



4. Intravenous Injection. The vein most 

 usually chosen is one of the auricular veins. 

 The part has the hair removed, the skin is 

 purified, and the vein made prominent by press- 

 ing on it between the point of inoculation and 

 the heart. The needle is then plunged into the 

 vein, and the fluid injected. That it has per- 

 forated the vessel will be shown by the escape 

 of a little blood; and that the injection has 

 taken place into the lumen of the vessel will be 

 known by the absence of the small swelling 

 which occurs in subcutaneous injections. If 

 preferred, the vein may be first laid bare by 

 snipping the skin over it. The needle is then 

 introduced. 



5. Inoculation into the Anterior Chamber of 

 the Eye. Local anaesthesia is established by 



applying a few drops of 2 per cent, solution of hydrochlorate of 

 cocaine. The eye is fixed by pinching up the orbital conjunctiva 

 with a pair of fine forceps, and, the edge of the cornea being 

 perforated by the hypodermic needle, the injection is easily 

 accomplished. 



Sometimes inoculations are made by planting small pieces of 

 pathological tissues in the subcutaneous tissue. This is especially 

 done in the case of glanders and tubercle. The skin over the 

 back is purified, and the hair cut. A small incision is made with 

 a sterile knife, and the skin being separated from the subjacent 

 tissues by means of the ends of a blunt pair of forceps, a little 

 pocket is formed into which a piece of the suspected tissue is 

 inserted. The wound is then closed with a suture, and collodion 

 is applied. In the case of guinea-pigs, the abdominal wall is to 

 be preferred as the site of inoculation, as the skin over the back 

 is extremely thick. 



Injections are sometimes made into other parts of the body, 

 e.g., the pleurae, the cranium, the spinal canal. With regard to 

 the last, Ford-Robertson has pointed out that in the rabbit it 

 can be easily practised through the space between the seventh 

 lumbar and first sacral vertebrae. The spine of the former 

 lies in a line with the iliac crests. With regard to operative 

 procedures in special regions of the body, it is unnecessary to 

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