124 ORGANISATION AFTER SUPPURATION. 



size may persist for some length of time, and maintain their 

 connexion with the organism. 



g 102. As regards vascularisation, in the course of repair by 

 second intention more particuhirly, the distribution of the em- 

 Ijryonic tissue upon a level surface affords favourable opportu- 

 nities for the access of pabulum. Never thelesSj an abundant 

 development of new vessels sets in here at a very early period to 

 promote this object. The histological details of the process are 

 the same as in the secondary mode of vascularisation ; along 

 certain lines running througli the parenchyma which is to be 

 vascularised a closer aggregation of the cells becomes apparent ; 

 a cord or row of cells becomes visible, pointing out the form 

 and direction of the future blood-path. But how is a cylinder 

 of cells converted into a tube ? How is the new vessel opened 

 up ? These questions can only be answered by a reference to the 

 discoveries of Thiersch, alluded to under the head of repair by 

 the hrst intention. Since the pervious parent-vessels, on which 

 both limbs of the newly-formed loops rest, are also shrouded hi 

 ii dense mass of cells, the most enigmatical part of the entire 

 process is withdrawn from direct observation. We know that at 

 a certain time the blood makes its appearance in the axis of the 

 cellular cord, that the cells of which the latter consists are 

 pushed asunder by the stream, and proceed forthwith to form 

 ■the Avail of the new vessel. I presume that the cells of which 

 the wall of the parent-vessel is made up are everywhere 

 loosened by the inflammatory irritation, thus ceasing to offer any 

 special hindrance to the tunnelling of a channel for the blood. 

 Some such hypothesis is indispensable for the due appreciation of 

 the farther progress of vascularisation, during which the newly- 

 formed vessels, which are still wholly made up of cells, give rise 

 in their turn to new vascular loops. The development of capil- 

 laries from within keeps pace with the formation of layer upon 

 layer of new embryonic tissue upon the surface. The capillary 

 loops, with their long parallel limbs, struggle vertically upwards 

 into the granulations ; they reach nearly as far as the suj^pm^at- 

 ing surface, their points of curvature being somewhat dilated 

 <%39). 



§ 103. This brings us to the point at which the formative 

 process is most luxuriant. Supposing progress in this direction 

 to be unrestrained, it may lead to another morbid deviation, sc. 



