692 PHILOSOPH[CAL TRANSACTIONS. [aNNO 1702. 



from the crista galli ; a, its lower limbus that touched the corpus callosum, as 

 it divides the right iiemisphere of the brain from the left, where the fifth sinus 

 passes, which is here dried and disappears ; b b the second process of the dura 

 mater, which supported the hin<imost parts of the lobes of the brain, and de- 

 fended the cerebellum from being pressed by those parts of the cerebrum ; c a 

 portion of the dura mater remaining to the longitudinal sinus ; dd several trunks 

 of the veins of the brain, cut off before they enter the longitudinal sinus ; ee 

 the longitudinal sinuses ; fp the two lateral sinuses ; g the fourth sinus ; g the 

 veins from the plexus choroides ; hh the buibi, or diverticula, at the beginnings 

 of the internal jugular veins ; ii the internal jugular veins; kk the trunks of 

 veins, which bring blood from the lower jaw and parts adjacent. 



Fig. 8, represents the trunks of the vena portae, dissected and displayed. 

 AA the branches of the vena portse, freed from the liver ; a the umbilical vein ; 

 B the splenic branch ; cc the mesenteric branches which are continued from 

 the intestines ; b the trunk of the vena pancreatica, which receives branches 

 also from the duodenum ; cc the vena gastrica dextra coronaria superior ; d the 

 superior coronary vein of the stomach of the left side; e the inferior coronary 

 branch of the stomach of the right side: and f the same coronary vein of the 

 left side, removed from their proper situations ; from these last two are con- 

 tinued the vena epiploica superior dextra 1, and the sinistra 1, with the media 

 3 ; G the vein called vas breve ; d the vena duodeni ; h the vena haemorroidalis, 

 arising from the rectum and anus, in this subject emptying itself into the left 

 mesenteric branch ; but in othir bodies I find this trunk of the hasmorroid 

 veins ending in the ramus splenicus. 



The length of the trunk of this haemorroid vein, and its progress under the 

 intc^stines, render it liable to be compressed, and its refluent blood retarded ; 

 whence its branches in the intestinum rectum and anus become distended with 

 blood, and cause the haemorroides caecas and apertae ; wliich are frequently at- 

 tended with aposthumations in the anus and parts adjacent ; which disorders are 

 the more incident, not only because these hsemorroid veins, like the rest of 

 the branches of the vena portse, are without valves, and the blood has an 

 ascending progress in them together, that the long trunk (h) is not only 

 exposed to the compressions made by the intestines in both sexes, but particu- 

 larly the uterus in women in time of gestation, especially near the birth, so 

 compresses this trunk, that it is no wonder we find women more afflicted with 

 the hsemorroids at that time, than at any other. Nor are the iliac veins, and 

 the lymphaduct that accompany them, without being exposed to the like in- 

 cumbrance in women with child, whence the veins of the legs and thighs be- 

 come varicose, and those limbs are so frequently swoln ; which, in a late 



