ANIMAL INOCULATION 93 



For the cornea a few scratches made in the corneal tissue 

 will suffice; the material is then gently rubbed in. 



Inoculation of the Cerebral Membranes. The skin 

 and aponeurosis cut through where the skull is the thinnest. 

 Then the bone carefully trephined, and the dura exposed. In 

 rabies inoculation, the syringe containing the hydrophobia 

 virus pierces the dura and arachnoid, and the virus is dis- 

 charged beneath the latter. 



Fig- 37- Method of making an intravenous injection into a rabbit. 

 Observe that the needle enters the posterior vein from the hairy sur- 

 face. 



Intratracheal. The bacteria can be introduced directly 

 into the trachea, thus coming in contact with the lungs. 



Intraduodenal. Cholera germs are injected into the in- 

 testines after they have been exposed by carefully opening 

 the abdomen. This is done in order to avoid the action of 

 the gastric juice. 



Celloidin sacs of small size are sometimes used to intro- 



