140 



SPECIAL HISTOLOGY. 



tain the red pulp 'of the spleen and the Malpighian corpuscles, 

 and although no one exactly resembles another, yet all as 

 regards form and size, present a certain similarity. 



The older anatomists considered them to be regular cavities 

 lined by a membrane, like those of the corpora cavernosa penis, 

 to which, indeed, they are very similar in the arrangement of 

 the limitary trabecule, but there is nothing of this kind, as 

 may be best demonstrated in sections of the spleen, in which 

 pulp has been removed by washing. Such a preparation is 

 best fitted for the study of the relations and connexions of the 

 trabecule; and it is readily seen, that although very various in 

 size, they do not ramify after the fashion of vessels, but unite 

 quite irregularly. Where 4, 5, or more of these unequally 

 thick trabecules unite, a flattened cylindrical enlargement, like 

 a nervous ganglion, usually exists; these are more frequent 

 towards the external surface of the organ than in its internal 

 portions and at the hilus, where the large vessels already 

 afford a sufficient support to the parenchyma and an intimate 

 union of the trabecules is less necessary. 



The structure of the trabecules of the human spleen perfectly 

 resembles that of the fibrous coat ; they consist of longitudinally 

 fibrous connective tissue, with inter- 

 mingled fine elastic fibres. In animals, 

 on the other hand, smooth muscles 

 exist, as I shewed in the year 1846, 

 sometimes in all the trabecules (Pig, 

 Dog, Cat), sometimes (Ox,) only in the 

 smaller ones, with respect to whose 

 distribution further particulars will 

 be found in my ' Mikroskopische 

 Anatomie/ II, 2, p. 256. In the tra- 

 becules also, we find peculiar spindle- 

 shaped fibres, of 0-02 — O03'" in length 

 and 0*002 /// in breadth, with undulated 

 ends and prominent enlargements, in 

 which rounded nuclei are situated. 

 They are to be met with in great 

 numbers in the splenic pulp of Man (fig. 227 A), and I 

 formerly, though as I now believe wrongly, took them to be 



Fig. 227. Peculiar fibres from the pulp of the human spleen : A, the same free 

 B, one inclosed in a cell ; x 350. 



