Animal Inoculations 



237 



injection, vasomotor dilatation occurs and the blood-vessels 

 become larger and more conspicuous. The vein should be 

 compressed at the root of the ear until the needle is intro- 

 duced, and the injection made as near the root as possible. 

 The fluid should be slowly injected. 



Bacteria can be introduced into the lymphatics only by 

 injecting liquid cultures of them into some organ with com- 

 paratively few blood-vessels and large numbers of lym- 

 phatics. The testicle is best adapted to this purpose, the 

 needle being introduced deeply into the organ. 



Sometimes subcutaneous inoculations are made by intro- 

 ducing the platinum 

 wire through a small 

 opening made in the 

 skin by a snip of the 

 scissors. By this 

 means solid cultures 

 from agar-agar, etc., 

 can be introduced. 



Intra-abdominal 

 and intrapleural in- 

 jections are some- 

 times made, and in 

 cases where it be- 

 comes necessary to 

 determine the pres- 

 ence or absence of 

 the bacilli of tuber- 

 culosis or glanders in 

 fragments of tissue 

 it may be necessary 

 to introduce small 

 pieces of the sus- 

 pected tissue under the skin. To do this the hair is closely 

 cut over the point of election, which is generally on the 

 abdomen, near the groin, the skin picked up with forceps, 

 a snip made through it, and the points of the scissors intro- 

 duced for an inch or so and then separated. By this man- 

 oeuver a subcutaneous pocket is formed, into which the 

 tissue is easily forced. The opening should not be large 

 enough to require subsequent stitching. 



When tissue fragments or collodion capsules are to be in- 

 troduced into the abdominal cavity, the animal should be 



Fig. 62. Method of making an intra- 

 venous injection into a rabbit. Observe 

 that the needle enters the posterior vein 

 from the hairy surface. 



