ANIMAL INOCULATION IN BACTERIOLOGY 299 



Note. Solid substances, larger than leucocytes, and air bubbles 

 should not be injected into the vascular system. Fatal emboli may 

 result. Return of blood through the needle indicates that the vein 

 has been entered. If swelling occurs at point of inoculation the inocu- 

 lum is entering the subcutaneous tissue. Try again. 



6. Intraabdominal or intraperitoneal. I. The site for 

 the operation is the center of the angle formed by the last 

 rib, transverse processes of the lumbar vertebrae, and the 

 external angle of the ilium. 



(a) Plunge the needle or trocar and canula through the 

 abdominal wall with one thrust. 



Note. When the parietal peritoneum is punctured the sudden 

 disappearance of resistance to the entrance of the needle is noticed. 

 The intestines will not be entered if pressure on the needle stops at 

 this point. 



(6) Inject the material and remove the needle, placing 

 the thumb and finger on each side of the needle and press- 

 ing gently on the skin during the removal so as to prevent 

 separating the skin and underlying layers of tissue. 



II. Infectious material or cultures in a sterile collodium 

 capsule may be introduced into the abdominal cavity by 

 performing laparotomy. (General anesthesia is desired.) 



6. Intraorbital. Always perform under local anesthesia. 

 (2% cocaine hydrochloride.) 



I. Steady the eye with fixation forceps. 



II. Pierce the cornea near to its periphery with a fine 

 needle. The needle should incline with the point outward 

 so that, upon entering the anterior chamber of the eye, 

 the iris will not be damaged. 



III. Inject the material. 



7. Subdural. Operate under general anesthesia. 



I. Make a longitudinal incision through the skin at one 

 side of the sagittal suture. Hold back the skin and sub- 

 cutaneous tissue with tenacula. 



II. Make a crucial incision through the periosteum and 

 push back the four corners. 



