CHAPTER XII. 



Inoculation of animals— Subcutaneous inoculation ; intravenous injection 

 —Inoculation into the great serous cavities, and into the anterior chamber of 

 the eye— Observation of animals after inoculation. 



After subjecting an organism to the methods of 

 study that we have thus far reviewed there remains to 

 be tested its action upon animals — i. e., to determine if 

 it possesses the property of producing disease or not, 

 and, if so, what are the pathological results of its 

 growth in the tissues of these animals, and in what way 

 must it gain entrance to the tissues in order to produce 

 these results ? The mode of deciding these points is by 

 inoculation, which is practised in different ways accord- 

 ing to circumstances. Most commonly a bit of the 

 culture to be tested is simply introduced beneath the 

 skin of the animal, but in other cases it may be neces- 

 sary to introduce it directly into the vascular or lym- 

 phatic circulation or into one or the other of the great 

 serous cavities; or, for still other purposes of observa- 

 tion, into the anterior chamber of the eye, upon the iris. 



Subcutaneous Inoculation of Animals. — The 

 animals usually employed in the laboratory for purposes 

 of inoculation are white mice, gray house-mice, guinea- 

 pigs, rabbits, and pigeons. 



For simple subcutaneous inoculation the steps in the 

 process are practically the same in all cases. The hair 

 or feathers are to be carefully removed. If the skin is 

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



