i>H'!i^SlCAL AND LITERARY. 487 



fes. -Upoti dijffedlion, we obferve arte- 

 ries opening, at lead into fome of them, 

 as I fhall afterwards prove, and confide- 

 rable veins are continued from all of 

 them; the veins and finufes having all 

 large communications with each other ; 

 and, though feme of the finufts may have- 

 Only two or three fmall veins opening in- 

 to them ; yet, in general, the diameter of 

 the veins continued from them is not 

 greatly inferior to that of the finus. 



Since, from this defcription, it ap-^' 

 pearSjthat thefe cavities are only the fome- 

 what dilated e^itremities of the branches 

 of the veins, we may account for their 

 formation, from the more than ordinary 

 difficulty there is in the return of the 

 blood from xhi gravid litenn ; which be- 

 ing therefore accumulated, muft ftretch' 

 all the veins greatly, but fuch parts of 

 fhem mofl as refift the lead j confequent- 

 ly their extremities, which are only cover- 

 ed by the lax internal cellular membrane 

 of the womb, will be moft dilated', or put 

 on the appearance of fmules ; and this 

 effed will be moft confpicuous where the 



greatefl 



