I004 Veterinary Obstetrics 



which is continuous with the external layer of the vessel walls, 

 adheres to the divided ends of the vessels, and becomes retracted 

 along with them, serving to close over the broken ends and form 

 a fibrous network which offers an impassible barrier for the blood 

 or urine. 



The umbilic vein, having very thin walls, collapses at once 

 after rupture, so that its lumen is closed and what blood remains 

 within, being free from any cardiac or capillary pressure, soon 

 coagulates and blocks the remaining cavity. The Whartonian 

 gelatine included within the cord rapidly loses its fluid portion, 

 which oozes away from the broken end ; within a few hours 

 the navel becomes dessicated to a hard, dry crust, which hermet- 

 ically seals the surface of the wound, and aseptic healing occurs 

 beneath the scab. 



Prior to the hermetic sealing of the wound by dessication, it 

 is open to infections of an extended variety, which acquire special 

 significance because of the vulnerability of the tissues involved. 



The tissues of the umbilic cord, including the urachus, veins 

 and arteries, invested with connective tissue and Whartonian 

 gelatine, become dormant when the cord ruptures, and possess 

 little or no power of resistance against bacterial invasion. The 

 conditions prevailing at this epoch rather invite infection, as the 

 tissues provide abundant moisture, nutrient material and warmth 

 for bacterial growth. 



Opportunities for infection are not wanting. Even before the 

 fetus has escaped from the vulva or the cord has ruptured, any 

 infection existing in the vulvo-vaginal canal of the mother may 

 have acquired a habitat on or in the cord. Nocard and others 

 hold that the appallingly fatal infectious diarrhea of calves is due 

 chiefly to navel infection, and that the infection is already lying 

 in wait in the vulvo-vaginal canal of the cow when the calf is 

 being born. Later, when the cord ruptures, the umbilic stump 

 is readily brought in contact with the earth, bedding, dung, 

 urine, etc., whence it may acquire virulent infections. 



The anatomy of the part permits the infection to reach the 

 circulatory system by a short route through the inert, open 

 umbilic vein, and to be carried thence to remote parts. 



