18 PROFESSOR THOMAS I) WIGHT. 



category, but which seems to be a step between it and the 

 normal arrangement, and which, I think, strengthens this theory. 

 It is reported by Bastien,^ and seems to have escaped notice. In 

 a foetus at term, in which there is no mention of other anom- 

 alies, the common iliacs united at the proper place to form the 

 vena cava, which ascended on the right of the aorta to its usual 

 termination, receiving the right renal on its way. A vein from 

 the left common iliac, and of about the same size, passed under 

 the left common iliac artery, and ascended along the left of the 

 aorta, receiving the left renal vein, and becoming a large vessel. 

 It pierced the pillar of the diaphragm somewhat earlier than 

 the aorta, and then passed behind the aorta to ascend in the 

 right chest on its right, and behind the vena cava. Its termina- 

 tion was that of the azygos. This seems really to be a case of 

 persistence of the posterior parts of both posterior cardinals, 

 the inferior cava having been formed in the usual way, but 

 without the shifting to it of the left renal vein. Had the 

 tributary of the hepatic which forms the cava been wanting, the 

 arrangement would have been that of the present case. 



The great system of anastomoses which appears to accom- 

 pany the development of the renal veins accounts for the 

 plexuses and the dilatations, doubtless the sequels of plexuses, 

 which are seen so often when there is high union of the ihac 

 veins. Sometimes a dilatation is found at this spot when the 

 iliacs unite at the usual place. Almost invariably in these 

 cases the renal vein which crosses the median line passes behind 

 the aorta. 



Of the above 23 cases, including mine, of absence of the 

 inferior cava below the diaphragm, only 6 are stated to have 

 been observed in foetuses, and 1 (Abernethy's) on an infant under 

 a year. In most of these cases there were conditions that made 

 life impossible. Possibly some of the others, of which I have 

 not seen the original account, may have been of the same age, 

 but it is clear that this anomaly does not of itself interfere with 

 life. Dorsch's case and mine both reached advanced age, which 

 in the latter is the more remarkable on account of the small 

 size of the vessels and particularly of the anomalous vein, which 

 latter is an unique observation. 



' Gazette MMcmIc dc Paris, 1860, p. 90. 



