2/0 PRACTICAL MICROSCOPY. 



The first operation is that of finding the vessel we wish 

 to inject, such as the artery of the kidney, or the hepatic 

 vein of the liver. An opening being made, one of the 

 small pipes of the syringe is thrust in and 

 tied round with a piece of waxed silk, so 

 that there may be no danger of withdraw- 

 ing the pipe before the conclusion of the 

 operation. All the vessels communicating 

 with the one in which the pipe is connected 

 must now be tied with silk to prevent the 

 escape of the injecting fluid, and several 

 pairs of bull-nose forceps should be at hand 

 FIG. 223. f r th e purpose of closing any which may 



by accident have been left open. 



Before the pipe is inserted a little of the injecting fluid 

 should be drawn up to fill it. When all is ready, the 

 syringe should be filled and emptied a few times with the 

 fluid in order to get rid of all air, especially below the 

 stopcock, and fitted to the pipe already in the prepara- 

 tion. With a firm pressure the syringe must be about 

 three-fourths emptied, again refilled and injected until the 

 operation is complete. 



When size is employed, after having tied up the vessel 

 where the pipe was inserted, the whole should be left in 

 cold water for five or six hours, in order that the size may 

 thoroughly set, after which sections may be cut as directed 

 in Chap. VIII. 



Injected specimens may be preserved in glycerine or in 

 a mixture of equal parts of alcohol and water, until required 

 for examination ; carbolic acid water is also useful for this 

 purpose. 



