SUBCUTANEOUS INOCULATION OF ANIMALS 227 



phatics by way of the testicles. The operation is in no wise 

 complicated. One simply plunges the point of the hypo- 

 dermic needle directly into the substance of the testicle and 

 then injects the amount desired. Injections made in this 

 manner are usually followed by instructive pathological 

 lesions of the lymphatic apparatus of the abdomen. 



Inoculation into the Great Serous Cavities. Inoculation into 

 the peritoneum presents no difficulties if fluids are to be 

 introduced. In this case one makes, with a pair of sterilized 

 scissors, a small nick through the skin down to the under- 

 lying fasciae, and, taking a fold of the abdominal wall between 

 the fingers, plunges the hypodermic needle through the 

 opening just made directly into the peritoneal cavity. There 

 is little or no danger of penetrating 'the intestines or other 

 internal viscera if the puncture be made along the median 

 line at about midway between the end of the sternum 

 and the symphysis pubis. Though this may seem a rude 

 method it is rare that the intestines are penetrated or other- 

 wise injured. The object of the primary incision is to lessen 

 the chances of contamination by bacteria located in the skin, 

 some of which might adhere to the needle if it were plunged 

 directly through the skin, and thus complicate the results. 



If solid substances, bits of tissue, etc., are to be intro- 

 duced into the peritoneum, it becomes necessary to conduct 

 the operation under an anesthetic and upon the lines of a 

 laparotomy. The hair should be shaved from a small area 

 over the median line, after which the skin is to be thoroughly 

 washed. A short longitudinal incision (about 2 cm. long) 

 is then to be made in the median line through the skin and 

 down to the fasciae. Two subcutaneous sutures, as em- 

 ployed by Halsted, are then to be introduced transversely 

 to the line of incision about 1 cm. apart, and their ends left 



