22 BOYINE OBSTETRICS 



The umbilical vessicle is a diverticulum of the intestines, 

 situated externally to the abdominal cavity. These two com- 

 municate through the ductus omphalcentericus. The umbilical 

 vesicle of the bovine foetus is reduced to thread size in the 

 sixth week. It is of no importance in obstetrics. 



UMBILICAL COED AND VAGINA UMBILIOALIS. 



The navel string {funis) is composed of the urachus, two 

 umbilical arteries, two umbilical veins and the remains of the 

 umbilical vesicle— the latter of no importance in advanced 

 pregnancy. All these are imbedded in a gelatinous mass, the 

 so-called "Gelatine of "Wharton" {Gelatina Whartoniana). 

 This substance is a mucoid tissue, its histological analogue 

 being the vitreous humor of the eye. This mucoid tissue 

 is difficult to separate from the umbilical cord. The umbilical 

 cord's sheath {vagina umMlicalis) is a continuation of the 

 amnion. At the continuation of the foetal integument a 

 distinct line of demarcation is noticeable. The skin of the 

 belly continues some centimetres beyond this sheath, this 

 portion being known as skin-navel. The external face of the 

 sheath shows epithelium and glycogenic plaques, its interaal 

 face being covered with endothelium. 



The iirachus begins at the fundus of the urinary bladder. 

 It lies in Wharton's Gelatine, and loses itself in the allantois. 

 It carries the urine of the bladder into the allantois and is 

 still open at the time of birth. 



The umbilical arteries {arteria umhilicales) spring from the 

 internal iliac arteries. They pass along the bladder, help 

 to form its round ligaments, embrace the urachus, pass 

 through the skin-navel and reach the umbilical cord. Usually 

 both umbilical arteries anastomose by transverse communica- 

 tion about the middle of the funis. They supply the amnion 

 and ramify in the chorion. The smaller vessels go to the 

 foetal placenta and ramify in the capillaries which lie in 

 the villi of the foetal placenta below the epithelium. The 

 umbilical veins {vence umhilicales) arise from the capillaries 

 of the chorial villi, which empty at first into smaller, later 



