436 MANUAL OF HISTOLOGY. 



bed. These interstices have been named the intermediate pulp-pas- 



We have to thank W. Miiller for being the first to place the existence 

 of these lacunae beyond doubt, although such an arrangement of parts 

 had been already pointed out here and there. Our own observations on 

 the spleens of the sheep, rabbit, Guinea-pig, mouse, mole, and human 

 being, have led us to the same conclusions on the subject as those arrived 

 at by the gentleman just mentioned. 



To understand correctly, however, the nature of these pulp-passages, it 

 will be necessary to return for a moment to those ultimate ramifications 

 of the arteria lienalis already dealt with in section 230. There we con- 

 sidered fully the capillaries of the simply infiltrated arterial sheaths of 

 the lymphoid swellings on the latter and of the Malpigliian corpuscles. 

 In all these parts, either the usual structure of the capillary tube was 

 presented to us, or a modified and much thinner wall indicative of its 

 approaching transformation. 



But all these capillaries to which we referred make their way into the 

 pulp of the spleen, becoming merged, after a shorter or longer course, in 

 the wall-less passages of the tissue, either single or branching. We not 

 unfrequently meet with spleens whose pulp must be said to be rich in 



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- 





Fig. 423. From the spleen of the hedgehog (after W. Mutter). , pulp 

 with its intermediate streams; 6, follicle; c, bounding layer of the 

 same; g, its capillaries; e, transition of the same into the intermediate 

 interstitial pulp-streams ; /, transverse section of an artery at the border 

 of the Afalpighian corpuscle. 



long capillaries, which occupy the axes of the pulp-cords in a way 

 reminding us of the lymph tubes. 



As to the mode now in which these capillaries run out, the following 

 points may be recognised (fig. 423). The walls of the little vessels become, 

 as they are about to run out, finer and thinner without exception, besides 

 which they appear delicately granular, as well as richly studded, with 

 nuclei imbedded in their substance. Subsequently we notice a regular 

 fibrillation commencing in the tissue of the wall, the nuclei, with the 

 portion of tissue adjacent, developing into separate bands and fibres, pale 

 in colour, which are inserted continuously into the reticulum of the 

 pulp. We are often uncertain, indeed, for some distance, whether we 

 have still before us the passage of a capillary on the eve of termination, 

 or a canal-like interstice of the pulp. Naturally, at these points, the 

 matters injected into the capillaries find their way into the adjacent por- 

 tions -of the pulp. 



