170 GENERAL ANATOMY. 



rior of the membrane, at the spots where the pellets are placed 

 without. The points in which these different objects are 

 found, are those where the membrane is most vascular. The 

 fringes contain in their thickness, cellular tissue, fat and blood 

 vessels: the other parts of the synovial membranes only re- 

 ceive serous vessels. Lymphatics are apparent in some of 

 these membranes only; it is useless again to revert to the 

 theory of Mascagni which this author applies to all the trans- 

 parent membranes. The nerves of the synovial capsules are 

 not known. 



217. The liquid secreted by these membranes or the sy- 

 novia, synovia, so named by Paracelsus on account of its im- 

 perfect resemblance to the white of egg, is the result of a per- 

 spiratory secretion, although various other opinions have been 

 entertained about the mechanism of its formation. This fluid 

 is not, as it was for a long time thought to be, the product of 

 a mixture of serum and fat; the marrow of the bones does 

 not transude to form it as we have seen; the synovia, in its 

 natural state does not even contain any oil. The supposed 

 glands of Havers can not, from what we have said, fulfil the 

 functions ascribed to them, and the fringes that surmount 

 them, are not, as he thought, excretory ducts: it is but very 

 lately, however, that this glandular structure has been sup- 

 posed to have been found; in fact, nothing glandular can be 

 observed in the synovial masses, no granulations nor excre- 

 tory ducts.* Even the fat they contain is not essential to 

 their structure, and besides, as there is no oil in the synovia, 

 it is not from the transudation of the first of these fluids, when 

 it exists, that the second owes its origin. Rosenmuller pre- 

 tends that there are secretory follicles in these adipose pellets: 

 I have never seen these follicles, nor do I know that any one 

 since has proved their existence. The secretion of the syno- 

 via then, is neither glandular, follicular, nor a simple result of 

 transudation, but truly perspiratory; it has its seat throughout 

 the whole extent of the synovial membranes, that portion of 

 them, particularly, which surmounts the fringes, and which 



* See Hey liters, Dissertatio physiol. ana/, de fabrica arlicul, 1803. 



