BLOODVESSELS OF SEROUS MEMBRANES. 273 



It remains to be mentioned that in specimens of the tunica 

 adventitia both of the blood and of the larger valved lymph- 

 atics of the mesentery of the Frog, prepared with nitrate of 

 silver, a beautiful pattern appears, presenting the closest simi- 

 larity to the distribution of the serous canals. 



For the study of the lymphatics of the serous membranes, 

 the best means that can be adopted is the examination of 

 objects impregnated with silver, and pencilled, or still better 

 unpencilled, and specimens self-injected from the serous cavities. 



For more minute details the reader is referred to the excel- 

 lent works of Recklinghausen, Dybkowsky,. Ludwig, and 

 Schweigger-Seidel. 



D. BLOODVESSELS. 



The capillary bloodvessels, as Dybkowsky has shown, form 

 wide plexuses in the intercostal and sterno-costal pleura, the 

 larger branches being accompanied by lymphatics.. The capil- 

 laries of the pleura communicate freely with those of the fasciae 

 as far as to the commencement of the muscular tissue. That 

 portion of the pleura that covers the ribs- frequently appears 

 to be particularly well supplied with blood capillaries. 



In the parietal lamina of the pericardium the larger blood- 

 vessels penetrate from without, and break up towards the 

 inner surface into a tolerably close capillary system. 



In the mesentery the larger trunks running radially from its 

 root towards the intestine, branch in an arborescent manner, 

 giving off' smaller and still smaller twigs, and ultimately losing 

 themselves towards the surface in a wide-meshed capillary 

 expansion. 



In the centrum tendineum of the Rabbit the larger vessels, 

 according to Ludwig and Schweigger-Seidel, enter for the most 

 part from the thoracic surface to reach the deeper portion of the 

 serosa, and more rarely from the abdominal surface ; the smaller 

 branches penetrate through the tendinous substratum, and run 

 in the spaces between the fasciculi of the radiating fibrous 

 layer ; to the borders of these they appear to be adherent, not 

 by means of their adventitia, but by a delicate membrane 

 extending over them. The capillaries of the matrix of the tho- 

 racic and abdominal surfaces form a wide-meshed plexus. 



VOL. II. T 



