MICROSCOPIC ANATOMY OF THE ORGAXti. 



nuclei can be seen to run at right angles to the nuclei of the 

 endothelial cells (Fig. 87). The inner connective-tissue coat 

 contains many elastic fibres which are fused together to form 



FIG. 87. 



Muscle nuclei Nuclei of endothelial layer 

 cut transversely 



Connect ire tissue nuclei of ^ udei f 



t. adventitia Clrcul j ar 7 



muscle layer 



Longitudinal section of a small artery from the lymph gland of a cat. x 600. 



the so-called fenestrated membrane of Henle. This forms the 

 innermost coat of the intirna, and in cross-section has the 

 appearance of a wavy refractive line running around the lumen 



Artery 



FIG. 88. 

 Small vein 



Med\ 



] 



Hlonil 





\ 



%ar*'Vv 



\ 



Media 



Endothelinm 



Epithe!i " 



Cross-section through a small artery and a corresponding view of a dog. x 220. 



of the vessel. It is colored bright yellow in any stain contain- 

 ing picric acid (e. cj., van Gieson's fluid). From fresh arteries 

 it can be dissected out, and pieces of the membrane of a con- 



