456 Drs. Herring and Simpson. Relation of the [May 31, 



by a grant from the Moray fund for the prosecution of research in the 

 University of Edinburgh. 



The Injection of the Liver Cells from the Blood-vessels : Method employed. 



The injection material we have used in the majority of our experiments 

 was carmine gelatine made up according to Carter's formula. The solutions 

 of gelatine and ammoniacal carmine were filtered separately and very 

 carefully, then mixed and rendered slightly, but distinctly, acid with acetic 

 acid. With such an injection mass there is no staining of tissues, and no 

 diffusion through the walls of ordinary capillaries. On some occasions we 

 used Prussian blue gelatine and also watery Prussian blue, but we found both 

 of these too diffusible ; nor do they allow of such good fixation of the tissues 

 as can be got by putting carmine gelatine injected preparations into cold 

 formalin. We also tried thick suspensions of Chinese ink, and in one case 

 hog's lard melted and filtered. Of all these, the carmine gelatine mass has 

 given by far the best results. 



The apparatus used for injection consisted of a large pressure bottle with 

 rubber pump attached and another tube leading to a bottle containing the 

 injection mass. A T-shaped junction on its course was led off to a mercury 

 manometer, which indicated the pressure employed. The bottle containing 

 the injection mass was immersed in a large bath of warm water ; the mass 

 flowed from it along a rubber tube to the cannula. 



The injection was made as soon after death as possible. The animals were 

 killed either by an overdose of chloroform or by coal gas. The thorax or 

 abdomen was opened and the cannula tied to the aorta or the portal vein. 

 The rubber tube and cannula were carefully filled with injection mass, to the 

 complete exclusion of air bubbles, a side tube being adapted to the cannula to 

 facilitate this. This side tube being then closed and the animal immersed in 

 the water bath, the pressure was gradually raised by pumping air into the 

 pressure bottle, the inferior vena cava having first been opened above the 

 diaphragm to allow the free escape of blood. When the injection was made 

 by the portal vein we ligatured the inferior vena cava below the liver to 

 prevent any backward flow through the large veins to other parts of the 

 abdomen. We did not, as a general rule, wash out the blood-vessels by the 

 previous injection of salt solution, but when this was done we had a second 

 bottle containing the saline solution attached by T-tubes to the same system ; 

 by opening and closing clips on the tubing we could inject either with 

 carmine gelatine or with salt solution. The fluids injected, bottles, tubing, 

 and animal were kept at body temperature by complete immersion in the 

 water bath. The washing out of the blood-vessels by salt solution is 



