116 OEGANISATIOX OP 



mation, and are exliibitcd in precisely the same manner by tlie 

 conjoint vascnlar and connective-tissne system, -whether the 

 wounded organ be the skin, or a muscle, or perchance the hver. 

 There certainly exists a mode of reunion which takes place 

 with such extraordinary rapidity by the mere apposition of the 

 cut surfaces, that no exuded matei'ial is required to complete it. 

 The occurrence of this immediate iimoii {Macartneif) is confirmed 

 by Thiersch in Pitha and Billroth's Manual of Surgery. It 

 must therefore take precedence of union by first intention. Li 

 the latter mode, a substance is usuall}' present which glues the 

 edges of the wound together. It appears a A'ery few hours after 

 the injury, and proves, both at first sight and on more careful 

 investigation, to be the connective tissue of the cut surface, infil- 

 trated with blood-corpuscles and serum, and swollen by imbibi- 

 tion of the latter fluid. The next stage of the process consist:> 

 in the migration of colourless corpuscles from the dilated vessels 

 In the immediate neighbourhood. They permeate the whole of 

 the cementing medium and the adjacent connective tissue, so 

 that the divided parts are at length united by a continuous layer 

 of embryonic tissue. The next step Is the re-establishment of 

 the circulation, which has been violently interrupted. This takes 

 place as a general rule by the method of ^^ secondary vascu- 

 larlsatlon" (^ 71), starting from those capillaries which are still 

 pervious. Thiersch has recently furnished us with the details of 

 the process. Should his interpretation of them be confirmed, 

 they will materially extend our ideas respecting the development 

 of new vessels in general. Thiersch found the cut ends of the 

 vessels, a few hours after the Injury, plugged by a corpuscular 

 proliferation, and somewhat dilated, but seldom occupied by a 

 blood-clot. Injecting the vessels at this stage with a warm solution 

 of gelatin, and hardening the preparation In alcohol, he found : 

 1. Sticking to the surface of the club-shaped plug of gelatin, 

 endothelial cells, some detached and isolated, others mider- 

 going proliferation. 2. A peculiar configuration of the surface 

 of the plug. This exhibited a number of thorny, seemingly 

 broken-off splcula, which perforated the wall of the vessel, and 

 proved on closer examination to be the radicles of a very beau- 

 tiful system of intercellular canals, filled with gelatin. Thiersch 

 sees in this system of canals a provisional nutrient apparatus, a 

 preliminary vascularisation, and proceeds on this view to explain 



