NAVEL ILL. 517 



NATURE AND CAUSE.— While the unborn foal (foetus) is in 

 the womb of its mother, it is surrounded by enveloping mem- 

 branes which constitute the after-birth on delivery. These mem- 

 branes 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 subsequently 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 vein become quickly blocked up, urine is discharged 

 through the urethra (which communicates with the penis or vagina, 

 as the case rnay be), the foal enjoys a separate existence, and the 

 wound, caused by the division of the umbilical cord, leaves a scar 

 known as the navel. 



It is usually supposed that the microbes of navel ill gain admit- 

 tance into the body through the exposed surface, before the wound 

 has closed. We read, however, in the " Veterinary Record '' of 

 14:th Dec, 1901, that Sohule has shown that "the mother is 

 the bearer of the infection, for in the uterine secretions of the 

 stud mares whose foals fell with navel ill, the same characteristic 

 bacteria were found as were present in the joints of the affected 

 foals. The infectious material is by the act of covering conveyed 

 from mare to mare, so that the mucous membrane of the womb 

 becomes the habitat of the specific bacteria. 



" By inoculation of these bacteria into the blood stream of foals 

 an illness was produced, which in the smallest particular could not 

 be distinguished from that arising in naturally affected foals." If 

 the infected microbes are transmitted by the dam, it is a strange 

 fact that their presence does not produce any disturbance in her. 



INFLUENCE OF LOCALITY.— Although, as a rule, this is a 

 rare disease, it is very common in some places. Several instances 

 are on record of particular farms, where they were unable to raise 

 either' foals or calves. On removing the mares, however, to 

 another farm immediately after or before foaling, the foals were 

 reared without difficulty. .Although constitutional debility plays 

 an important part, the presence of specific organisms constituting 

 an infected area is the most important factor in producing this 

 disease. 



MORTALITY. — About 75 per cent, of the oases die within the 

 first three weeks after birth. This high rate of mortality would be 

 considerably diminished, if proper treatment was adopted. 



