504 VETERINARY PHYSIOLOGY 



period. Advantage has been taken of the fact that the 

 blood of different individuals belongs to one of four groups as 

 regards power of agglutinating cells of other groups. If a man 

 be transfused with a blood which does not belong to his group, 

 specimens of his blood treated with a serum which agglutinates 

 his corpuscles leaves the transfused corpuscles unagglutinated. 

 It has been found that this condition may last for over a 

 month, indicating that the corpuscles have continued in the 

 blood for this period of time. The methods are unsatisfactory, 

 and the results must be accepted with reservation. 



The method of disposal of old and effete erythrocytes in the 

 body has been studied by ^^oisoning them with various 

 reagents such as phenylhydrazin. It is then found that 

 they are removed from the circulation more especially by 

 two orcjans. 



1. The Liver. 



In the endothelial cells lining the capillaries, erythrocytes 

 in all stages of disintegration may be seen, and the iron of 

 the haemoglobin in a compound, or series of compounds, 

 generally called haemosiderin, may be demonstrated by the 

 green colour developed by treating with hydrochloric acid 

 and potassium ferrocyanide. When haemoglobin is set free 

 in the plasma, it is chiefly taken up by the true liver cells. 

 That the pigment is split up and the iron-free part excreted 

 is shown by the presence of the bile pigments in the bile. 



2. The Spleen. 



1. Structure. — This organ is composed of a fibrous 

 capsule containing visceral muscle, and of a sj)onge-work of 

 fibrous and muscular trabecular, in the interstices of which is 

 the spleen pulp. The branches of the splenic artery run in 

 the trabecule, and twigs pass out from these trabecule, and 

 are covered with masses of lymph tissue forming the 

 Malpighian corpuscles. Beyond these, the vessels open into 

 a series of complex sinusoids, lined by large prominent 

 endothelial cells. From these capillary sinuses the blood is 

 collected into channels, the venous sinuses, which carry it 



