DISEASES OF THE HORSE 55 



NAVEL STRING INFECTION 

 (Umbilical Pyemia) 



Cause and Natuke: While the unborn foal (foetus) 

 is in the womb of its mother, it is surrounded by envelop- 

 ing membranes which constitute the after-birth on deliv- 

 ery. These membranes are attached to the wall of the 

 womb and are connected to the foetus by means of the 

 navel-string (umbilical cord) which is provided with two 

 arteries and a vein for the nourishment of the young 

 creature and for the removal of its waste products. 



It also has a narrow canal (the urachus) which serves 

 to remove the urine of the foetus ; in fact the subsequent- 

 ly formed bladder takes its origin from a dilation of the 

 urachus. Under normal conditions when the foal is born, 

 respiration takes place, the umbilical arteries and veins 

 become quickly blocked up, urine is discharged through 

 the urethra (which communicates with the penis or va- 

 gina, as the case may be), the foal enjoys a separate 

 existence and the wound caused by the division of the 

 umbilical cord leaves a scar which is known as the navel. 



It is usually supposed that the germ of navel-string 

 infection gains admittance into the body through the ex- 

 posed surface before the wound is closed. However, I 

 am of the opinion that the mother is the bearer of the 

 infection in a great many cases for in the uterine secre- 

 tions of mares whose foals fell with navel-string infec- 

 tion, the same characteristic germs were found as were 

 present in the joints of the affected foals. The infec- 

 tious material is, by the act of covering, conveyed from 

 mare to mare, so that the mucous membranes of the 

 womb becomes the habitat of the specific germ. By in- 

 oculation of these germs into the blood stream of foals an 

 illness is produced which in the smallest particular can- 

 not be distinguished from that arising in naturally af- 

 fected foals. It is a strange fact that when the infected 

 germs are transmitted by the mother, their presence does 

 not produce any disturbance in her. 



