436 ANATOMICAL AND PATHOLOGICAL OBSERVATIONS. 



XXVIL THE STKUCTUKE OF THE SEROUS 

 MEMBRANES. 



A PORTION of the human pleura or peritoneum will be found 

 to consist, from its free surface inwards, of a layer of nucleated 

 scales, of a germinal membrane,* and of the sub-serous 

 areolar texture intermixed with occasional elastic fibres. 

 The bloodvessels of the serous membrane ramify in the 

 areolar texture. 



There is one stratum only of the nucleated scales in the 

 superficial layer of the serous membrane. This layer con- 

 ceals the germinal membrane, which can only be detected 

 after the removal of the scales. 



The germinal membrane does not in general show the 

 lines of junction of its component flattened cells. These 

 appear to be elongated in the form of ribbons their nuclei, 

 or the germinal spots of the membrane, being elongated, ex- 

 panded at one extremity, pointed at the other, and somewhat 

 bent upon themselves. The direction of these flattened cells 

 and nuclei is the same in any one part of the membrane, this 

 direction being in general parallel to the subjacent blood- 

 vessels, in the neighbourhood of which they exist in greatest 

 numbers. The germinal spots are bright and crystalline, and 

 may, or may not, according to their condition, contain smaller 

 cells in their interior. They are not to be confounded with 



* I stated this fact in my Paper on the Intestinal Villi, in the Ed. Phil. 

 Journal, July 1822. Dr. Todd and Mr. Bowman, in their Physiology of 

 Man, have described the same membrane in the serous texture. 



