receive from it, the biood ou which they are to act. The liver is also- 

 comprised in the sphere of activity of the duodenum, since the distension 

 of that intestine irritates it, determines a more copious flow of its fluids, 

 and a more abudant secretion of bile. 



C. The blood which is sent to a secretory gland, before reaching it, un- 

 dergoes preparatory changes, which dispose it to furnish the materials of 

 the fluid which is to be separated from it. We have seen, in treating of 

 digestion, how the blood which the vena portae sends to the liver, is fit 

 for the secretion of bile. There can be no doubt, that the portion of 

 blood which it carries to the testicles, by the long, slender, and tortuous 

 spermatic arteries, undergoes changes*, which bring it nearer to the se- 

 minal fluid. 



The rapidity with which the blood flows into an organ, the length, the 

 diameter, the direction, the angles of its vessels, the arrangement of their 

 extreme ramifications, which may be stellated, as in the liver, in fasciculi, 

 as in the spleen, convoluted, as in the testicles, Sec. are circumstances 

 which should be taken into account in the study of each secretion, since 

 all have some influence on the nature of the fluid secreted, and on the 

 manner in which the secretion is effected. 



The fluid which lubricates the whole extent of the moveable surfaces 

 by which the bones of the skeleton are articulated together, is not exclu- 

 sively prepared by the membranous capsules which envelope the articu- 

 lations. A number of reddish coloured cellular substances, placed in 

 their vicinity, co-operate in the secretion. Though these parts, which 

 were long considered as synovial glands, do not completely resemble the 

 conglomerate glands, and although no glandular bodies, nor excretory 

 ducts, can be demonstrated in them, they cannot, however, but be consi- 

 dered as fulfilling, to a certain degree, the same functions, and one must 

 admit that they are of some utility, in the secretion of the synovia. They 

 are always met with; their extent and bulk are always proportioned to 

 the extent of the auricular .surfaces, and to the frequency of motion in 

 the joints near which they are situated. They are found in all animals ; 

 pale and light coloured in those which have been long at rest; red, high- 

 ly vascular, and bearing the marks of a kind of inflammatory diathesis, 

 in those which have been compelled to violent exercise, as the oxen which 

 are brought to Paris from distant provinces, and the wild animals which 

 have been hunted. In anchylosis, they are less red and of greater con- 

 sistence, than in a healthy state. 



When, from the irritation attending friction, the fluids are determined 

 towards an articulation which is in motion, do they not then, by passing 

 through those glandulo-cellular bodies, undergo a peculiar modification 

 which renders them fitter for the secretion of synovia. This would not 

 be the only instance, in the human body, of parts whose action is but se- 

 condary and connected with that of other organs principally engaged in a 

 secretion whose materials are contained in the blood which passes through 

 them. It will be urged, no doubt, that this preparatory apparatus is not 

 met with in the neighborhood of the great cavities , but it should be re- 



* By this loose expression one might be induced to suppose that the changes here al- 

 luded to were spontaneous, or chemical. It should have been said that the peculiar or- 

 ganization of the spermatic vessels seems designed to produce the changes which bring 

 the blood nearer in character to the Seminal fluid. Godman, 



