AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, JULY 12 
ABSENCE OF THE VENA CAVA INFERIOR IN A 12-MM. 
PIG EMBRYO, ASSOCIATED WITH THE DRAINAGE 
OF THE PORTAL SYSTEM INTO THE CARDINAL 
SYSTEM 
ALEXANDER 8. BEGG 
Harvard Medical School, Boston, Massachusetts 
THREE FIGURES 
Anomalies of the adult venous system due to faulty develop- 
ment of the cardinal veins in the embryo have frequently been 
recorded. Naturally those in man have received the greatest 
attention from anatomists, and the number of cases reported is 
quite large. From Petsche’s report in 1736 to the present year 
I find more than 150 cases of human anomalies definitely asso- 
ciated with the cardinal system in its relation to the inferior vena 
cava, and this number does not include the numerous cases limited 
strictly to the azygos veins. Other mammals have likewise been 
studied with reference to these veins; in fact, the earliest record 
of an abnormal condition appears to be the peculiar doubling 
of the vena cava inferior in a dog, recorded and figured by Kerck- 
ring in 1670. After a long series of observations on the eat, 
carried out with admirable thoroughness, Huntington, McClure 
and Darrach have elaborately classified the variations in this 
animal. Other observations include those of Hall on the rabbit, 
Korosky on the dog, Phisalix and Zumstein on the guinea-pig, 
Keith on gibbons, and other observers upon development and 
variations in many forms. 
A study of the reported cases reveals interesting difficulties in 
regard to nomenclature and classification. There are, on one 
hand, cases in which the vena cava inferior is said to be double 
when the normal single vessel is but partially developed and, on 
the other hand, the vena cava inferior is said to be absent when 
the component parts are all present save one. This recalls 
Professor Dwight’s query, ‘‘ What constitutes the vena cava in- 
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