G2 Proceedings of Philosophical Societies. [Jutr, 



Last year we mentioned a treatise of Professor Jacobsen, the 

 contents of which were then examined by a committee. This 

 being done, we are now enabled to give a more complete account 

 of it. The author had already, several years ago, begun to 

 inquire into the venous systems of reptiles and birds, of which he 

 had published something ; but in the treatise of which we speak 

 here ; he has not only united all this, but also arranged and con- 

 siderably enlarged his researches. The author has found that 

 most part of the veins that in man and mammalia lead into the 

 system of the vena cava, in reptiles and birds go into the kidneys 

 and the liver ; for the branches of the vena portae are not con- 

 fined to the viscera chylopoietica, but spread also into the 

 remote parts of the bodies (the tail, and the thigh, &c), and 

 there receive veins which in man are branches of the vena cava. 

 This form and regulation of the system of veins in reptiles and 

 birds is different in the different classes of animals. In the frog, 

 the lizard, and the tortoise, it begins in the belly from the kid- 

 neys, with two or five strong lateral branches (vena? renales 

 interna? superiores), and from the genitals. The veins from the 

 hinder part of the animals, vena lumbalis, the sciatic vein, and 

 vena caudalis, do not join the vena cava; but on running into 

 the pelvis form two principal branches, the one of which so. vena 

 renalis inferior, that is produced by the uniting of the vena cau- 

 dalis and vena sciatica, bends forwards towards the kidney, and 

 ramifies in this organ like the vena porta? in the liver. The 

 other branch is formed by the vena lumbaris, and by the veins 

 from an organ peculiar to these animals (organon hvpogastricum), 

 and either goes towards the middle line of the anterior part of the 

 belly there to join (as in the frog) its companion from the oppo- 

 site side of the body, and thus jointly to constitute one single 

 principal branch (vena abdominalis anterior) that ascends to the 

 liver, and enters the trunk of the vena porta? ; ci there is no 

 union (for instance, in the tortoise), but the veins on both sides 

 run parallel to the liver and vena porta?. In most reptiles a con- 

 siderable uniting branch is found between the vemikunbaris and 

 the sciatic vein, so that all the veins from the hind part are 

 united as well with the vena renalis inferior, as also with the 

 vena abdominalis anterior. In the snakes that have no legs, 

 consequently no vena? lumbares, the vena caudalis only forms 

 the vena renalis inferior, but the vena abdominalis rises from the 

 organon hypogastricum, and from the muscles of the belly. la 

 the snake is also wanting (as it has no legs) the uniting 

 branches between the vena lumbalis and the vena renalis, so that 

 both the principal branches as well vena renalis inferior as 

 vena abdominalis anterior in these animals are entirely separated. 



A similar regulation or constitution has also been observed by 



the author in buds, though with some differences, of which this 



is the principal, that some part of the blood that comes from the 



binder part of the body is iuunediatelv led into the vena cava. 



6 



