CHAPTER XII. 



Inoculation of Animals — Subcutaneous Inoculation — Intravenous Injec- 

 tion — Inoculation into the Lymphatic Circulation — 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 on 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 animals, 

 and in what way must it gain entrance to the tissues in 

 order to produce those results ? The mode of deciding these 

 points is by inoculation, which is practised in different ways 

 according to circumstances. Most commonly, a bit of the 

 culture to be tested is simply deposited beneath the skin of 

 the animal; but in other cases it may be necessary to intro- 

 duce it directly into the vascular or lymphatic circulation, 

 or into one or the other of the great serous cavities; or, 

 for still other purposes of observation, into the anterior 

 chamber of the eye, upon the iris or within the skull cavity, 

 upon the dura or brain substance. 



SUBCUTANEOUS INOCULATION OF ANIMALS. 



The animals usually employed in the laboratory for pur- 

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

 pigs, rabbits, and pigeons. 



For simple subcutaneous inoculation the steps in the 

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