INTUMESCENTIJE. 589 



formed by the extremities of lymphatics may be interrupted by 

 an obstruction of these vessels, or at least of the conglobate 

 glands through which these vessels pass. This, however, is very 

 doubtful. As the lymphatics have branches frequently com- 

 municating with one another, it is not probable that the obstruc- 

 tion of any one, or even several of these, can have any consider- 

 able effect in interrupting the absorption of their extremities. 



And for the same reason, it is as little probable that the ob- 

 struction of conglobate glands can have such an effect : at least 

 it is only an obstruction of the glands of the mesentery, through 

 which so considerable a portion of the lymph passes, than can 

 possibly have the effect of interrupting absorption. But even 

 this we should not readily suppose, there being reason to be- 

 lieve that these glands, even in a considerably tumefied state, 

 are not entirely obstructed: and, accordingly, I have known 

 several instances of the most part of the mesenteric glands being 

 considerably tumefied, without either interrupting the trans- 

 mission of fluids to the blood-vessels, or occasioning any dropsy. 



An hydropic swelling, indeed, seems often to affect the arm 

 from a tumour of the axillary gland ; but it seems to me doubt- 

 ful, whether the tumour of the arm may not be owing to some 

 compression of the axillary vein rather than to an obstruction 

 of the lymphatics. 



MDCLXVI. A particular interruption of absorption may 

 be supposed to take place in the brain. As no lymphatic ves- 

 sels have yet very certainly been discovered in that organ, it 

 may be thought that the absorption, which certainly takes place 

 there, is performed by the extremities of veins, or by vessels that 

 carry the fluid directly into the veins ; so that any impediment 

 to the free motion of the blood in the veins of the brain, may 

 interrupt the absorption there, and occasion that accumulation 

 of serous fluid which so frequently occurs from a congestion of 

 blood in these veins. But I give all this as a matter of con- 

 jecture only. 



" Prognosis of dropsy. We determine whether a case be 

 curable or incurable a priori from the consideration of its causes. 

 Among incurable dropsies, we may rank, in the first place, the 

 hy drops hydatideus : again of the cases more distinctly under- 

 stood, those depending upon certain organic affections which, 



