INOCULATION OF ANIMALS 139 



it has perforated 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 pinch- 

 ing 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 

 describe these, as the application of the general principles 

 employed above, together with those of modern aseptic surgery, 

 will sufficiently guide the investigator as to the technique which 

 is requisite. 



After inoculation, the animals ought to be kept in comfortable 

 cages, which must be capable of easy and thorough disinfection 

 subsequently. For this purpose galvanised iron wire cages are 

 the best. They can easily be sterilised by boiling them in the 

 large fish-kettle which it is useful to have in a bacteriological 

 laboratory for such a purpose. It is preferable to have the 

 cages opening from above. Otherwise material which may be 

 infective may be scratched out of the cage by the animal. The 

 general condition of the animal is to be observed, how far it 

 differs from the normal, whether there is increased rapidity of 



