130 INOCULATION OF ANIMALS. 



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 accom- 

 plished. 



Sometimes inoculations are made by planting small 

 pieces of pathological tissues in the subcutaneous tissue. 

 This is especially used 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 and the cranium. 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 com- 

 fortable cages, which must be capable subsequently of easy 

 and thorough disinfection. 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. Other- 

 wise 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 breathing, 

 etc. The temperature is usually to be taken. This is 

 generally done per rectum. The thermometer (the ordinary 

 5 min. clinical variety) is smeared with vaseline, and the 

 bulb inserted just within the sphincter, where it is allowed 



