510 



SPLEEN. 



[CHAP. xxxv. 



about the 300th of an inch in length, and about the ^ o 

 an inch broad in the centre, which is their widest part. They 

 contain a distinct elongated or oval nucleus. The nucleus is often 

 found bulging upon one side of the fibre cell, and in some instances 

 appears only connected with it by a stalk. The cell is often much 

 curved, and sometimes bent upon itself, an appearance arising from 

 its mode of development, which takes place, according to the obser- 

 vations of Mr. II. Gray, by the solution of the cell wall at a point 

 opposite the nucleus, which latter remains, and the cell wall itself 

 forms the fibres which are prolonged from either side of it. 



Fi g, 246. In several of the mam- 



malia, both in the capsule 

 and also in the trabeculse, 

 a number of muscular fibre 

 cells, with a distinctly oval 

 elongated nucleus, are pre- 

 sent. The fibre may be en- 

 tirely composed of these 

 cells. They are not present 

 in the human spleen, but 

 may be readily demonstrated 

 in that of the sheep. The 

 spleen possesses very slight 

 power of contractility, and 

 in experiments upon the 

 spleen of the ox and sheep, 

 Mr. Gray was unable to ob- 

 tain marked contractions by 

 the application of a strong 

 galvanic current. 



Spleen Pulp. The spleen 

 pulp, or parenchyma, the 

 proper tissue of the spleen, is composed of peculiar colourless 

 cells, containing masses of colouring matter, free coloured particles, 

 granular matter, and blood corpuscles. 



The colourless portion of the spleen pulp is composed principally 

 of small circular cells, or nuclei, about the size of a blood corpuscle, 

 and having a faintly granular appearance. These small nuclei vary 

 somewhat in size, and are interspersed with a considerable quantity 

 of granular matter, which is often collected around them. The 

 spleen pulp also contains a few nucleated vesicles, nearly yoVoth of 

 an inch in diameter. 



Muscular fibre cells from the spleen of the sheep, mag- 

 nified 400 diameters, a. a. Fibres more highly magnified. 

 After Mr. Gray. 



