Anatomy of seuous membranes. 153 



surrounding it proliferates, and after a time the process, 

 gradually becoming longer and thicker, is enveloped by 

 a covering of young endothelial cells. In a further stage the 

 process itself divides into several distinct cells, and we have a 

 cone or knob, the centre of which is formed of young cells, 

 clearly distinguished from the covering of young endo- 

 thelia. 



{b) In the second place, the endothelium which borders a 

 stoma, itself grows luxuriantly and projects freely from the 

 surface. Two or three endothelial cells may be seen to ele- 

 vate themselves on a pedicle from the serous surface, and 

 become drawn out lengthways. Other cells doing the same, 

 a long thin cord is produced Avhicli depends from the surface. 

 In a further stage a distinct homogeneous axial cord may be 

 seen enveloped by the endothelial cells ; this axis tapers away 

 towards the point from which the proliferation of endothe- 

 lium commenced and stops short near this point. Later on 

 this axis appears as a bundle of minute connective-tissue 

 fibrilla; which may be with great probability supposed to 

 arise from division, or, to use Rollett's expression, by a sort 

 of " coining" of the homogeneous mass. 



(c) The endothelium of the true stomata grows out in 

 cones, in such a manner that a cavity remains in the middle 

 which is a prolongation of the lymph-sinus to which the 

 stoma belonged. 



{d) A considerable number of the nodes projecting from 

 the surface owe their existence only to an excessive growth 

 of the nodes which occur in the normal omentum, on or near 

 the vascular sheaths or fatty lobules, or else in the fenestrated 

 portion. 



The cords described under the head {a) often grow into ex* 

 tremely long trabecular structures, the cells which form their 

 solid axis multiplying, becoming branched and separating 

 from one another. Tavo such cords may unite and form a 

 new node at their point of union, which node is then con- 

 nected by two bridges with other parts of the omentvim. 



The formation of vacuolse in the plasmatic canal-cells in the 

 chronic inflammatory process plays an important part. 

 Although the cells in which the vacuoles are formed appear to 

 be round cells without processes, it still appears probable 

 that they originate in flat branched plasmatic canal-cells, buds 

 from which being set free have become young cells. A vacuole 

 arises in a plasmatic cell and is prolonged into a process, Avhile 

 its wall divides into cellular plates ; then by opening into a 

 blood-capillary it may form a new blood-vessel, by opening 

 into a lymph sinus a new lymphatic vessel. Ciliated lymph 



