154 



SPECIAL HISTOLOGY, 



of 0-003 — 0-005'", which throughout the pulp, round the Mal- 

 pighian corpuscles, as well as elsewhere, unite into a somewhat 

 wider network. 



Fig. 232. 



With respect to the veins, I must especially express my- 

 self against the existence of the venous sinuses or spaces of 

 ancient and modern anatomists, in the human spleen. The 

 larger veins which still accompany arteries, present no pecu- 

 liarities, except in their width ; all possess a membrane, which is, 

 at least upon the side of the artery, easy of demonstration, and, 

 like the vascular sheath, gradually becomes thinner. Apertures 

 of more minute veins, the so-called stigmata Malpighii, exist 

 only in inconsiderable numbers in the largest of these veins, 

 while in the smaller, they are more fre'quent. From the point 

 of divarication of the arteries and veins, the relations of the 

 latter become somewhat different. In the first place, they give 

 off upon all sides a vast number of small veins, usually at right 

 angles, whence their walls appear in places almost cribriform ; 

 and secondly, their membranes become completely coalescent 

 with the sheaths of the vessels, so that ultimately the two con- 

 stitute only a single very delicate wall, which, however, may 



Fig. 232. An artery with its penicillate ends, from the spleen of the Pig, x 25. 



