1286 



PHYSIOLOGY 



of movements of the foetus. In many cases no antecedent stimulus can be 

 discovered, and the automatic contraction of the uterus seems to be analo- 



FIQ. 578. Diagrammatic outline of the organs of circulation in the 



foetus of six months* (After ALLEN THOMSON.) 



RA, right auricle of the heart ; RV, right ventricle ; LA, left auricle ; EV, Eustachian 

 valve ; LV, left ventricle ; L, liver ; K, left kidney ; I, portion of small intestine ; a, arch 

 of the aorta; a', its dorsal part; a*, lower end; vcs, superior vena cava; vci, inferior 

 vena where it joins the right auricle; vci', its lower end; s, subclavian vessels; 

 j, right jugular vein; c, common carotid arteries; four curved dotted arrow-lines ai 

 carried through the aortic and pulmonary opening and the auriculo-ventricular ori- 

 fices ; da, opposite to the one passing through the pulmonary artery marks the place 

 of the ductus arteriosus ; a similar arrow-lino is shown passing from the inferior vena 

 cava through the fossa ovalis of the right auricle and the foramen ovale into the left 

 auricle ; hv, the hepatic veins ; vp, vena porta? ; x to vci, the ductus venosus ; uv, 

 the umbilical vein; ua, umbilical arteries; uc, umbilical cord cut short; ii', iliac 



gous to that which occurs in the distended bladder. These contractions 

 ordinarily give rise to no sensations, and are felt only when they are aug- 

 mented in consequence of reflex stimulation. During the greater part of 



