.5J2 COLOURLESS CONSTITUENTS. [CHAP. XXXV. 



many instances corpuscles are seen evidently breaking up into 

 small irregular masses of red colouring matter. These appear- 

 ances indicate that the red blood corpuscles are undergoing a pro- 

 cess of disintegration, but this change also appears to be effected 

 in another and very peculiar manner, which was first described by 

 Kolliker. Several blood corpuscles (from one to nine or ten) 

 collected together, appear to become covered with an investing 

 membrane, adhering to the anterior wall of which, a distinct nucleus 

 may be observed. Such appears to be the manner in which these 

 blood corpuscle-holding cells are formed, but whether the nucleus 

 precedes the formation of the cell or succeeds it, is not known. The 

 blood globules within now undergo disintegration in the manner 

 just referred to, and at length the cell contains only coloured 

 granules, varying in size and form. These granules gradually be- 

 come of a golden yellow colour, and then paler, until at last the 

 contents of the cell become almost decolourized. 



Occasionally, red crystals are seen in the blood corpuscles of the 

 splenic parenchyma, as was first observed by Funke ; and not un- 

 frequently numerous free coloured acicular crystals are met with. 



These appear to be the most important changes which take place 

 in the disintegration of the red blood corpuscles in the spleen 

 pulp. In some animals, the disintegration seems to occur entirely 

 within the large cells; while in others, the blood corpuscle-holding 

 cells are very rarely met with, and the blood globules become 

 broken down into coloured granules without being at any time en- 

 closed in a cell. In other cases, again, both processes occur. In 

 the course of very numerous observations upon the human subject, 

 Mr. Gray only observed blood corpuscles enclosed in cells in two 

 instances, and then in very small number. 



We may observe here, that Gerlach interprets these facts in a 

 totally different manner, and considers that the changes taking 

 place in the blood corpuscle-holding cells occur in the reverse 

 order to that which we have described. In fact, he considers that 

 the blood corpuscles are formed in these cells, commencing as 

 irregular yellow granules, and gradually becoming developed into 

 the perfect red blood globule. In this view Virchow appears to 

 coincide. Dr. Hughes Bennett, of Edinburgh, also considers the 

 spleen as a blood-forming organ. 



The changes above referred to take place in the spleen pulp 

 which lies between the trabeculse, and, of course, external to the 

 capillary vessels. Now, we have to enquire how the blood corpuscles 

 leave the vessels and enter the pulp. 



