Account of the Dissection of a Human Fcetzts. 45 



an imperfect ccecum, but the colon was not distinguished 

 by any difference of structure or appearance from the rest of 

 the intestine. The rectum had ils usual situation in the 

 pelvis. The spleen and renal capsules were small ; the kid- 

 neys, bladder, penis, and testicles had the usual appearance. 

 The abdomen was lined by peritonaeum, but there was no 

 omentum. The liver and gall-bladder were wanting;. 



As there was no heart, it became an object of importance 

 to ascertain the exact nature of the circulation : for this pur- 

 pose the blood-vessels were traced with attention. 



The umbilical chord consisted of two vessels only : one of 

 these was larger than the other, and its coats resembled those 

 of a vein, while those of the sinallcr vessel were thick and 

 elastic, like those of an artery. Both of these vessels en- 

 tered the navel of the child. The artery passed to the left 

 groin by the side of the urachus, occupying the usual situa- 

 tion of the left umbilical artery. Here it gave off the external 

 and internal iliac arteries of the left side, and was then con- 

 tinued upwards on the fore-part of the spine formino^ the 

 aorta. From the aorta arose the common trunk of the right 

 iliac artery, and the branches to the viscera and parictes of 

 the thorax and abdomen. At the upper part of the thorax it 

 sent off the two subclavian, and afterwards divided into the 

 two carotid arteries, without forming an arch. The veins 

 corresponding to these arteries terminated in the vena cava, 

 which was situated on the anterior part of the spine before 

 the aorta, and passed downwards before the right kidney 

 to the right groin. Here it became reflected upwards by the 

 side of the urachus to the navel, and was continued into the 

 larger vessel or vein of the chord. 



It appears therefore, that, in this foetus, not only the 

 heart was wanting, but there was no connnunicatiou of any 

 kind between the trunks of the venous and arterial systems, 

 as in the natural foetus, where there is a heart. The only 

 communication between the two sets of vessels, was by 

 means of the capillary branches anastomosing as usual in the 

 foetus and in the placenta. The blood must have been pro- 

 pelled from the placenta to the child ihrouch the artery of 

 the chord, and must have been returned ty the placenta by 



means 



