252 Professor Clark on a Case 



are entirely different: the vesicle has four points of attachment 

 instead of two, it is pressed by equal forces in opposite directions, 

 and is kept at rest. Hence the upper coils of small intestine 

 were found much compressed with a very short mesentery, and 

 closely connected to the walls of the vesicle: whilst the lower 

 bowels were disproportionately developed, and the mesentery 

 much extended between them and the spinal columns. If this 

 explanation be accepted it sets the question at rest concerning the 

 existence of an open duct of communication between the umbilical 

 vesicle and the small intestines in the human embryo, a commu- 

 nication which has been denied by great authorities, by Emmert, 

 Hoechstetter, and Cuvier. In a rare case, (Tiedemann, Anatomie 

 der kopflosen Missgeburten, tab. iv.), there was found a true um- 

 bilical vesicle attached to the intestinal canal. The foetus had 

 arrived at the full term, and was in many respects monstrous. 

 In Brugnoni's case it is very remarkable that the single duodenum 

 terminated in a vesicle, whilst the lower portion of the small in- 

 testines of each foetus were not connected with it, but commenced 

 as blind tubes. • 



The upper part of the intestine, that from which the oeso- 

 phagus, stomach, and anterior portions of the small intestine are 

 afterwards formed, was perhaps probably at its origin, and from 

 the first, a single tube connected to the spine of each embryo. 

 That it was formed from the parts appropriated to each I con- 

 clude to be a fact: because I observe that there are two pairs of 

 lungs with a trachea for each, and two livers. The appearance 

 also of the stomach and the presence of two spleens seems to in- 

 dicate that it has been formed from the rudiments of what ought 

 to have been two. The existence and the magnitude of the liver 

 on the left side of the drawing PI. 14. shews that the unintelli- 



