DISEASES OF THE GENERATIVE ORGANS. 



UEscraPTioN of plates. 



Plate XII. Fetal calf within its membranes (at mid term). The uteriTS is 

 opened on the left side. In the uterus the fetus is surrounded by 

 several membranes which are known as the amnion or inner layer, the 

 allantois or central layer, and the chorion or outer layer. The amnion 

 is nearest the fetus and forms a closed sac around it filled with a 

 fluid known as liquor amnii, in which the fetus floats. The allantoia 

 is composed of two layers, which form a closed sac in connection with 

 the urachus, or the tube which extends from the fetal bladder through 

 the umbilical cord. The one layer of the allantois is spread over the 

 outer surface of the amnion and the other over the inner surface of 

 chorion. The allantois also contains a fluid which is known as the 

 allantoid liquid. The chorion is the outer envelope or membrane of 

 the fetus, completely inclosing the fetus with its other membranes. 

 On the outer surface of this membrane are found the fetal placentulfe, 

 or cotyledons, which, through their attachment to the maternal cotyle- 

 dons, furnish the fetus with the means of sustaining life. The relation 

 of the fetal and maternal cotyledons to each other is illustrated on the 

 following plate. 



Plate XIII. Pregnant uterus with cotyledons. 



Fig. 1. Uterus of the cow during pregnancy, laid open to show the coty- 

 ledons (d) on the internal surface of uterus (c). The ovary (a) is 

 shown cut across, and the two halves are laid open to show the position 

 of the discharged ovum at a'. 

 Fig. 2 illustrates the relation of the fetal and maternal parts of a coty- 

 ledon. A portion of the uterus (A) is shown with the maternal coty- 

 ledon (BB) attached to it. The fetal portion (/)) consists of a mass 

 of very minute hairlike processes on the chorion (E), which fit into 

 corresponding depressions or pits of the maternal portion. Each por- 

 tion is abundantly supplied with blood vessels, so tliat a ready inter- 

 change of nutritive fluid may take place between mother and fetus. 



Plate XIV. Vessels of umbilical cord. 



Fig. 1. Fetal calf Avith a portion of the wall of the abdominal cavity of 

 the right side and the stomach and intestines removed to illustrate 

 the nature of the umbilical or navel cord. It consists of a tube (1-1') 

 into which pass the two umbilical arteries (3) carrying blood to the 

 placenta in the uterus or womb and the umbilical vein (4) bringing 

 the blood back and carrying it into the liver. The cord also con- 

 tains the urachus (2') which carries urine from the bladder (2) 

 through the cord. These vessels are all obliterated at birth. 5, liver ; 

 5', lobe of same, known as the lobus Spiegelii ; 5", gall bladder; 6, 

 right kidney; 6', left kidney; 6", ureters, or the tubes conducting 

 the urine from the kidneys to the bladder ; 7, rectum, where it has 

 ben severed in removing the intestines ; 8, uterus of the fetus, cut off at 

 the anterior extremity; 9, aorta; 10, posterior vena cava. (Fi'om 

 Fiirstenberg-Leisering, Anatomic tmd Physiologic des Rindes.) 

 208 



