148 GENERAL ANATOMY. 



tions, those of the tendons and those which are subcutaneous. 

 We must first examine the characters common to all the genus, 

 and then those of the species. 



SECTION I. 



OF THE SEROUS MEMBRANES IN GENERAL. 



184. All these membranes consist of bladders closed on all 

 sides: there is no other exception to this general disposition, 

 than the opening by which the peritoneum communicates 

 with the genital organs in women, the continuity of these or- 

 gans themselves being interrupted between the ovary and the 

 commencement of the oviduct or fallopian tube. The result 

 of the general conformation of the serous membranes, is, that 

 the fluids they contain are entirely isolated, and that their 

 membranes are only permeable by the vessels that ramify in 

 their thickness, and not like the cellular tissue, by areolae freely 

 communicating with each other; this conformation presents, 

 however, some secondary forms or varieties. Some of these 

 membranes which are as simple as possible, resemble an am- 

 pulla or bladder; they are called vesicular. Others constitute 

 sheathing envelopes that surround certain parts such as the 

 tendons, ligaments and the blood vessels; and as they are not 

 pierced so as to allow these parts to pass, but are reflected at 

 their two extremities and so form a double sheath, they have 

 received the appellation of vaginiform. This disposition is 

 one of the most usual. There are some however that are still 

 more complex; they are the enveloping serous membranes, 

 those which more particularly merit the name of succingentes: 

 these latter surround the organs except at one single point of 

 their surface, about which they are reflected on to the parities 

 of the cavity which contains them, and are thus divided in 

 two portions, of which one forms an envelope for the organs, 

 and is called the visceral layer, or tunic, while the other 

 which lines the parietes, constitutes the parietal layer. The 



