GENERAL METHODS OF INVESTIGATION, BY S. STRICKER. XXXVll 



being carefully avoided. In order to obviate the inconveni- 

 ences of the method of injecting with warm fluids, Beale 

 recommends a fluid that can be used cold, consisting of colour- 

 ing matter, water, glycerine, and traces of hydrochloric acid. 

 When the organ has been injected, it is placed in absolute 

 alcohol, and then treated as before. This mode of injection 

 is very convenient, the vessels acquiring a very pretty colour ; 

 but they can only be used on organs possessing a certain con- 

 sistence. 



Lastly, the method of self-injection occupies an important 

 position amongst the various modes of injection. It has long 

 been practised in the case of the vascular system of the frog. 

 A pointed glass tube, filled with the coloured injecting fluid, 

 is inserted into the vena cava, and distributed through the 

 system by the force of the heart itself. Kiihne and Chrzon- 

 szczewsky have thus injected the biliary vessels of living 

 animals by means of colouring matter introduced by the 

 jugular vein. Toldt has very recently practised a similar 

 method for injecting the lymphatics. In the case of the 

 biliary ducts a colouring material (indigo-carmine) in solu- 

 tion is employed, in order that it may be transmitted through 

 the liver cells into the ducts ; but in the case of the lympha- 

 tics a granular pigment (anilin) precipitated by water from 

 its alcoholic solution, is introduced into the blood. Connected 

 with the introduction of granular pigment is the method 

 of colouring organs through the agency of the food, which 

 has of late years assumed so much importance. This subject 

 will be treated of at length in the first chapter of this work. 



