1819.] Royal Danish Society. 63 



The reason of this is, that the vena lumbaris on entering the 

 pelvis, forms two ramifications, the middlemost of which 

 joins the vena cava ; the uppermost goes immediately into the 

 kidneys; while the nethermost, together with the sciatic vein 

 and branches of the vena ossis sacri forms the vena renalis 

 inferior, which, for the most part, lies buried in the substance of 

 the kidneys. 



The peculiar organ which the author has found in the reptiles 

 consists of a serous membrane with many veins. This membrane 

 is formed like a bladder ; and in those reptiles whose skins are 

 without scale, it is united with the great gut, but in rep- 

 tiles covered with scales, the organ is not thus united, but is 

 filled with fat. The author does not believe that this difference 

 prevents us from concluding that this organ is the same in all these 

 animals, and supposes that the difference is only to be ascribed 

 to the skin's unequal aptness of respiration. This is, however, 

 by the committee of the Society, looked upon as dubious. 



After all this, the blood that proceeds from the hinder part 

 divides into two parts ; the first of which is led through the fore- 

 most vena abdominalis to the liver, where it associates with the 

 vena porta?, and thus contributes to prepare the gall ; the other 

 part, that proceeds from the sciatic vein and vena caudalis, goes 

 to the kidney ; and in the author's opinion serves to the secre- 

 tion of the urine. That the blood from the hinder part of the 

 body goes to the kidneys, as has been alleged, the author proves 

 as follow : a. That the vena renalis inferior, in all the animals here 

 mentioned examined by him, are connected with the sciatic vein 

 and the vena caudalis. b. That the said vena renalis grows 

 larger in proportion as it approaches the kidney, and as it pro- 

 ceeds receives more branches, whereas its greatness ao-ain 

 abates in proportion as it forms ramifications to the kidney, 

 c. That it ramifies so nicely in the kidney that immediate union 

 with the other vena; renales superiores and the vena cava can be 

 discovered, d. That even in those animals in which the con- 

 nexions of the vena abdominalis and the vena renalis inferior is 

 most exact, you may, by compressing the vena abdominalis, 

 hinder the blood from proceeding from the hinder extremities 

 to the liver without occasioning it to be stopped in the vena 

 sciatica and vena lumbaris ; whence it is evident that it must 

 flow off through the ramifications of the inferior vena renalis in 

 the kidney, c. Lastly, that there are animals, for instance, the 

 snake, in which the vena abdominalis anterior and the vena 

 renalis inferior are entirely separated, so that the blood from the 

 hinder parts of the body in these animals cannot flow but through 

 the vena renalis. That the blood thus led to the kidney serves 

 to secrete the urine, the author endeavours to prove from the 

 Hprending and nice ramifications of these veins in the kidneys ; 

 from the smallness of the arteria renalis that appears to be insuf- 

 ficient Xa the secretion of the urine in those animals ; and from 



