MINUTE ANATOMY OF THE ARTERIES. 269 



tained, situated between it and the next coat, the so-called 

 tunica media ; but, according to the observations of Kolliker,* 

 Gimbert/f" and myself, occupies a position intermediate between 

 the epithelium and the elastic inner tunic. Remak has desig- 

 nated this layer as the innermost longitudinal fibrous coat ; 

 Kolliker, as the striated layer of the internal coat. This coat 

 consists of a finely granular substance, with delicate fibrils 



Fig. 45. 



Fig. 45. Elastic internal tunic of the basilar arteries. 



running transversely and longitudinally. The greater part of 

 this tunic is destroyed by the action of potash. Externally, 

 this membrane becomes more distinctly fibrous, and gradually 

 passes into elastic networks and membranes. 



According to Langhans, J this layer is not distinctly fibrous 

 in young persons, but indistinctly granular, the striation first 

 becoming apparent after the membrane has attained a certain 

 thickness. 



The tissue of this membrane contains numerous fusiform 

 and stellate cells, lying in anastomosing canals, with relatively 

 large nuclei, and with either finely granular or quite homo- 

 geneous cell substance. Amongst these elements small granu- 

 lation cells are sometimes found, respecting which it is a matter 



* Handbuch der Gewebelehre, 5. Auflage, p. 583. 



t Memoire sur la structure et sur la texture des Arteres, Journal de 

 VAnatomie et de la Physiologic, par Charles Robin, p. 536, 1865. 

 \ Virchow's Archiv, Band xxxvi., p. 197, 1866. 



