364 PARENCHYMA OF THE SPLEEN. [sECT. 1 68. 



§ 168. The Red Splenic Substance, Splenic Pulp, or Parenchyma 

 {substantia rubra, pulposa, parenchyma lienis) is a soft reddish 

 substance, which fills up all the interspaces between the larger 

 trabecular and vessels, and, on account of its softness, may be 

 readily removed from a section of the spleen. It consists of three 

 elements, viz., of the most delicate blood-vessels of the spleen, mi- 

 croscopical fibres and trabecular, and peculiar parenchyma-cells. 

 With these elements in man and animals, blood, in various stages 

 of metamorphosis, is always found conjoined, so that it may almost 

 be regarded as a normal constituent of the pulp. According to the 

 quantity of this blood, and the degree of fulness of the blood- 

 vessels, the pulp appears of a clearer or of a darker blood-red 

 colour, although it is to be observed that the pulp also possesses 

 red colouring matter of its own. 



The fibres of the pulp are of two kinds. First, microscopical 

 trabecule, quite analogous to and of the same structure as the 

 larger ones which are seen by the naked eye, except that in many 

 mammalia they contain more smooth muscular fibres, or are even 

 composed of nothing else. Their diameter generally varies be- 

 tween CT005'" to croi'", and their number and quantity are not 

 uniform in different parts of the organ, nor in different animals. In 

 man, I find them more scanty and broader than in the lower mam- 

 malia, and in structure completely resembling the large trabecular. 

 The other fibres occurring in the pulp are obviously terminations 

 of the sheaths of the vessels. They are. met with in very large 

 numbers, and especially appear in the form of delicate membranes, 

 indistinctly fibrous in texture, without elastic tissue ;  they appear 

 to unite the capillaries, and are, perhaps, also connected with the 

 finest trabecular. 



The cells of the splenic pulp, or parenchyma- cells of the spleen, 

 are, for the most part, round cells with single nuclei, o , oo3" / to 

 CT005"' in diameter, and so similar to those of the Malpighian 

 corpuscle, that a detailed description is not needed. Free nuclei 

 are likewise found intermingled with them, in larger numbers than . 

 in the Malpighian corpuscles ; here, again, a more careful examin- 

 ation shows that the free nuclei occur accidentally only, perfect 

 cells alone being the essential constituents of the pulp. Besides 

 the foregoing, some other elements are noticed : — first, clear round 

 homogeneous bodies, somewhat larger than blood-corpuscles, which 

 appear to be smooth nuclei enclosed tightly by a thin envelope ; 

 secondly, large cells, measuring up to croi"' in diameter, quite 

 pale, with one or two nuclei; and, thirdly, there are found cells 



