DETERMINATION OF THE PATHOGENICITY OF AEROBES vii48-7 



crosses the elbow joint. If the material is considerably acid or alka- 

 line it is adjusted to pH 7.3. The coarse particles are removed. 

 Veins may be enlarged by rubbing with xylene or immersing them in 

 warm water; but xylene should be avoided if the resulting reaction 

 interferes with the test. They are washed off with alcohol before and 

 after the injection. HgCl2 should be used when working with highly 

 pathogenic cultures. The previously warmed material free from air 

 bubbles is slowly injected. Alcohol saturated cotton is then pressed 

 over the puncture until the bleeding stops. 



Intraperito7ieal. The disinfectant is applied as with subcutaneous 

 injection. The needle is passed through the skin and then through 

 the abdominal wall with a short stab. Caution: Avoid puncturing 

 the intestines and liver, the latter by injecting in a lower quadrant. 



Intrapleural. The procedure is the same as with intraperitoneal 

 injection except that one injects into the pleural cavity anterior to the 

 diaphragm, the point depending upon the experimental animal. 

 Caution: Avoid puncturing the lungs and pericardial sac. 



Per OS. Introduction of the material into the stomach or intestines 

 may be accomplished by a catheter or capsules or by mixing the 

 material with food or drink. To avoid exposure to the acid of the 

 stomach the material may be enclosed in enteric coated capsules. 

 Liquids may be mixed with starch and made into pills which are 

 digested in the intestines. Peristalsis can be controlled with mor- 

 phine. 



Per Rectum. 



Inhalation. Material for inhalation should be atomized in a 

 closed space about the head of the animal. (See Rosebury, 1947, 

 for complete details of inhalation technics). 



Insufflation. Light anaesthesia is necessary to quiet the animal 

 for insufflation. The material is blown into the trachea or bronchial 

 tubes through a tube introduced into the larynx. Liquid may be 

 passed into the trachea and then blown into the bronchia. In some 

 instances the material is dropped into the nostrils and the animal is 

 allowed to insufflate, or the material is sprayed onto the membranes 

 of the nose and throat. The use of force and anaesthesia may reduce 

 the resistance of the membranes. The results obtained vary with 

 the method used, which should be reported in detail. 



Intratracheal, Material may be introduced into the trachea 

 through a tube introduced into the larynx or by means of a syringe 

 through the side of the neck. In the latter method the skin may be 

 incised after shaving and sterilizing it. 



Ophthalmic. Material is dropped into one eye, the other serving 

 as a control. It may also be inoculated upon the scarified bulbar 

 conjunctiva or injected subconjunctivally. 



Intracranial. Injections are made into the brain through the skull. 



Intracerebral. The method varies with different species of animals 

 depending on the material and the desired location for the inoculum. 

 In most instances the material is deposited into one of the frontal 

 lobes. Caution: Do not use enough to cause pressure. For large 



