INJECTION OF LYMPHATICS. 177 



object the whole, or a portion only, is dissected off 

 under salt solution (it may be convenient to remove 

 with it the elongated kidneys which adhere to it 

 behind and to cut these away only after the staining 

 is completed) ; it is then rinsed in distilled water to 

 remove the salt ; placed in silver solution for one 

 minute; again rinsed, and exposed in water to the 

 light. After the metal is reduced the preparation 

 is floated on to a slide, and with the usual precau- 

 tions to avoid folds and creases, finally mounted in 

 glycerine. It is desirable, before mounting, to stain 

 the tissue with logwood in the way recommended 

 for the unbrushed silvered piece of the rabbit's 

 omentum, but this is not absolutely necessary, and 

 much increases the risk of producing folds in the 

 membrane. 



For studying the structure of the larger lymphatic 

 vessels, as, for example, the thoracic duct, precisely the 

 same methods, both for teased preparations and for sec- 

 tions, are employed as were used for the larger blood- 

 vessels. 



INJECTION OF LYMPHATICS. 



The minute lymphatics of a part may, where 

 numerous, generally be readily displayed by simply 

 sticking a very fine canula into the tissue, and 

 forcing a colored fluid through this. The best 

 apparatus for the purpose of obtaining the requisite 

 pressure is the small mercury apparatus shown in the 

 accompanying figure (Fig. 30). The mercury con- 

 tained in the bottle a compresses the air in the pres- 

 sure-bottle 6, according to the height a is raised 

 above 6, this height being regulated with the great- 

 est nicety by the screw d. The bottle c containing 

 the injection fluid communicates by one tube with 

 the pressure-bottle, and by another (which passes to 

 the bottom) with the injection canula f. Gelatine 

 is not used for injecting the lymphatics, but almost 

 always injections which are fluid iu the cold. Berlin 



