The Strïicture and Functions of the hannolymph Glands and Spleen. 41 



destructive effect can the spleen have upon blood corpuscles? The 

 argument, advanced against the breaking down of red cells, is that no 

 free haemoglobin is found in the splenic vein; this statement may 

 or msij not be correct, hut in a small vein of the spleen, I have 

 observed quantities of the bright ijelloiv pigment, so characteristic of 

 blood destruction. 



In the glands with which we are more particularly concerned at 

 present, pigment is found in abundance in the sinuses and adenoid 

 tissue, varying in colour from a bright golden yellow, to a deep orange 

 or brown, according to the density of its accumulation. Drumniond 

 and Warthin have both noticed the presence of free iron in the glands, 

 though the last observer has given no account of the methods which 

 he employed in identifying it. Drummond employed the potassium 

 ferrocyanide and hydrochloric acid method. I have used both this 

 method and that of Macallum, which consists in soaking alcohol 

 hardened sections for a few minutes in a dilute solution (1 in 300) 

 of hoematoxylin. Free iron particles are stained an intense black. 

 Sections so treated show small black granules similar to those seen 

 in liver cells, within the phagocytes and on the borders of the adenoid 

 tissue. It is probable that much of the haemoglobin of disintegrated 

 erythrocytes is completely reduced to an iron free pigment. 



There seems no reason to doubt that the process of blood destruction 

 in the spleen is identical with that in hsemolymph glands generally. 



The problem, as to the precise nature of the pigment, is harder 

 to solve. Vincent and Harrison considered it to be some form of 

 hiematin. As the substance is embedded either in the adenoid tissue 

 or in the phagocytes, microchemical tests are to large degree unsatis- 

 factory. In experiments on teased preparations, it has been found 

 that the pigment is, to a considerable extent, soluble in alkalies; 

 solutions of sufficient concentration, show, on spectroscopic examination, 

 absorption in the red and violet, but no bands are apparent. Further, 

 in many cases, the addition of a fuming concentrated solution of nitric 

 acid caused the appearance of a faint green colouration (Gmelin's 

 test). I am inclined to regard the pigment as closely allied to bilirubin, 

 if not, identical with it. There is no reason, to doubt the capability 



