OF THE SEROUS MEMBRANES IN GENERAL. 



organs, and of the glands, frequently derange their functions; 

 the affections of the organs they invest always produce a cor- 

 responding one in them, more or less evident; on the one hand, 

 the cavity they form establishes a complete isolation between 

 the parts on which their opposite portions are reflected; on 

 the other, the continuity and extent of these membranes, easily 

 give rise to very extensive affections. 



193. At its origin, about which however little is known, 

 the serous system is very soft: in the embryo the abdominal 

 viscera seem covered with a mere viscid and liquid varnish. 

 The serous membranes are very thin in the fretus, and in ge- 

 neral less adhesive, on account of the softness of the cellular 

 tissue which unites them to the neighbouring parts, so that 

 they are easily separated from these latter: in the articulating 

 cartilages, however, and in the albuginea of the testicle, the 

 adhesion is almost as great as at a later period. We are com- 

 pletely ignorant whether or not these membranes, whose essen- 

 tial character is the interruption of continuity they establish 

 between the parts, are at first a soft cellular tissue, continuous 

 and without an internal cavity, as is affirmed by some anato- 

 mists, who admit that in the beginning, there exists a general 

 continuity of all the parts ; among the bones, for instance. The 

 liquid of the serous membranes is at first very thin; some of 

 these membranes, those of the splanchnic cavities, present in 

 the foetus remarkable differences of conformation. In old age 

 the serous membranes undergo various changes. 



194. The conformation of an accidental serous tissue is 

 frequently observed; its reparatation or reproduction takes 

 place in wounds of the serous membranes, which reunite when 

 their edges are in direct contact; observation has shown the 

 opinion of the ancients, who did not believe this kind of wound 

 susceptible of reunion, to be totally void of foundation. When 

 these wounds are attended with loss of substance, or when 

 there is a separation of their edges, the space is filled up by a 

 new membrane, a true cicatrix; this appears a little thinner 

 and more extensible than the surrounding membrane. 



195. The liquid contained in the cavity of the serous 

 membranes is susceptible of accumulation either from the ab- 



