142 SPECIAL HISTOLOGY. 



part, been over-estimated, in consequence of their having been 

 incompletely isolated. Their diameter is from ^ — l ~", on the 

 average J'" ; and very probably depends upon the varying condi- 

 tion of the chylopoietic organs, so that the corpuscles are larger 

 after food has been taken than at other times ; though, in con- 

 firmation of Ecker's statement, I can affirm that they are to 

 be met with, beautifully developed, in fasting animals also. 

 We have no data of any kind with regard to this point in Man. 



The Malpighian corpuscles, though imbedded in the red pulp 

 and hardly separable from it, are nevertheless always attached 

 to a branch of an artery, in such a manner that they either 

 rest laterally immediately upon a vessel, or are situated in its 

 angle of division, or finally appear stalked; in which latter 

 case, however, the stalk itself, again, is usually a small artery. 

 Their number is very considerable, arterial twigs of 0*02 — O04"' 

 carrying 5 — 10 corpuscles, so that, extracted with them from 

 the pulp, they present the figure of an elegant raceme (fig. 228). 

 It appears to me that it would be rather under, than over esti- 

 mating the number of the Malpighian corpuscles, to assume 

 that every 1 — lj cubic line of the pulp contains a corpuscle. 



With respect to its minute structure, every Malpighian cor- 

 puscle possesses a special coat and contents, and is therefore 

 _ nnn a vesicle. The membrane is 



Fig. 229. 

 ^ colourless and transparent, O'OOl 



• . ^^gfggaggfe. — , 002 /// thick, and everywhere 



"/^IPlfi |gk exhibits a double contour, with 



igjl ;% occasional intermediate concen- 



hBB I III trie lines; it is intimately con- 



||||||/ nected with the sheath of the 



X^ 1 , , r-iy vessel, with which it also agrees 



""BHHI^^^^^^BBB \ m structure, so far as it contains 



'-jfe ■ l^lll^ ^^^^^ homogeneous connective tissue 



and elastic fibrils; whilst, on the 

 other hand, the smooth muscles which are also present as 

 longitudinal fibres in these sheaths, are entirely absent. In their 

 interior, the Malpighian corpuscles contain no epithelium, but 

 are entirely filled by a viscid, greyish, continuous substance, 



Fig. 229. A Malpighian corpuscle from the spleen of an Ox, x 150 : a, wall of 

 the corpuscle ; b, contents ; d, sheath ; and e, wall of the artery to which it is 

 attached. 



