SPLEEN. 



773 



torquatus, while it was absent in the rabbit, 

 horse, ox, hedgehog, guineapig, and bat. The 

 elastic fibres of this tunic are for the most 

 part much stronger than in man. 



Their peculiar vessels and nerves I have 

 never witnessed. 



3. The trabecular tissue, (trabecitlce lienis, 

 balks, or joists of the spleen), consists of white, 

 shining, flat or cylindrical fibres, which arise 

 in great numbers from the inner surface of the 

 fibrous coat; and, in smaller quantity, from 

 the exterior surface of the sheaths of the ves- 

 sels. These are so connected with similar 

 fibres in the interior of the spleen as to con- 

 stitute a network which extends throughout 

 the whole organ. Between the fibres of this 

 net exist a great number of spaces which are 

 connected with each other, and are occupied 

 by the red spleen-substance and splenic cor- 

 puscles ; and which, although very irregular in 

 respect of their form, and, as regards their 

 size, of the most variable dimensions, have yet 

 a considerable resemblance to each other. 

 The older anatomists regarded these spaces 

 as regular and uniform cavities provided with 

 a special membrane. But this last structure 

 nowhere exists, as may be verified in a spleen 

 in which, after short maceration, the pulp has 

 been removed from these spaces by washing. 

 Such a preparation will also afford the best 

 means of studying the mode of connection of 

 the fibres, and in this manner it may be seen 

 that, although they are of very different diame- 

 ters, yet the finer fibres are not everywhere 

 given off from the thicker ones. This is es- 

 pecially shown by the fact, that fibres of the 

 most different diameters are intimately con- 

 nected together at all points. Where four, five, 

 or more of these joists meet, there generally oc- 

 curs a knot of a flattened cylindrical form, 

 which is not unlike that of a nerve-ganglion. 

 Such knots are more frequently found to- 

 wards the outer surface of the organ, since the 

 cross-beams are more numerous .here than in 

 the interior. In this latter part, namely in the 

 neighbourhood of the great vessels, the nume- 

 rous ramifications of these tubes themselves 

 serve as points of support to the pulp, and 

 consequently render the joists less necessary. 



The structure of the trabecular tissue of the 

 human spleen completely corresponds with 

 that of the fibrous tunic, since it consists of 

 white fibrous tissue and the yellow fibres. 

 The former of these two structures exhibits 

 parallel fibrillye, which run without exception 

 in the direction of the long axis of the parti- 

 tion or joist, and rarely unite into individual 

 bundles. The latter consists of somewhat 

 finer and stronger yellow fibres, which anas- 

 tomose with each other ; their maximum di- 

 ameter is 1,1000th of a line: the greater 

 number of them lie between the bundles of 

 white fibrous tissue, and are easily recognised 

 by their irregular course and manifold curves. 

 Many anatomists, with Malpighi, had spoken 

 of muscular fibres in the partitions of the 

 spleen, although none had succeeded in de- 

 monstrating them, either with the scalpel or 

 microscope, or chemically. But in 1846 I dis- 



covered them with the aid of the microscope, 

 in the spleen of the pig.* Here they exist 

 both in the finest and largest of the partitions, 

 but they are not isolated, being connected 

 with the finer reticulations of the yellow fibres 

 (j%. 523.). In the larger partitions which are 



Fig. 5-23. 



A trabecula from the Spleen of the Pig, magnified 350 

 diameters, and treated with acetic acid. 



a, muscular fibre-cells with a projecting extremity, 

 or not isolated ; b, nuclei of the same ; c, elastic 

 fibres. 



visible to the naked eye, the muscular and 

 elastic fibres are present in pretty nearly equal 

 quantities, consequently these parts are to be 

 regarded as alike elastic and contractile. But 

 in the smallest and microscopic cross-beams 

 the muscular fibres predominate, and often 

 they appear to be even unmixed with elastic 

 fibres. In these parts the quantity of white 

 fibrous tissue is still smaller than that of the 

 yellow ; indeed,, in this animal it is but very 

 sparingly present in the larger partitions. The 

 direction of the fibres above-named is always 

 longitudinal or parallel to the long axis of the 

 joist, never transverse. In similar extent and 

 quantity, and with a like connection to the 

 elastic tissue, I have found muscular fibre in 

 the dog, the ass, the cat, the Dicotyles tor- 

 quatus, the sheep, rabbit, horse, hedgehog, 

 guineapig, and bat. In the ox, on the con- 

 trary, it exists only in the finer and micro-* 

 scopic partitions, where it is present in very 

 considerable quantity and in remarkable dis^ 

 tinctness. The remainder of the trabecular 

 tissue consists only of yellow fibre in m.ion, 



* Mittheilungen der naturforschenden Gesell 

 schaft in Zurich, 1847, S. 120. 



3 D 3 



