PROGRESS OF PROLAPSE OF THE ANUS. 



603 



project beyond the anus. In simple prolapsus ani et recti the ring- 

 shaped swelling shows an opening at its centre, through which faeces 

 are discharged ; at its periphery it is impossible to pass the finger 

 towards the pelvis. The case is different where prolapse is complicated 

 with invagination ; then the finger, and in large animals the entire 

 hand, can be introduced alongside the prolapsed part into the pelvic 

 portion of the rectum. It is of importance to note this, as it at once 

 differentiates the two conditions, and affords important indications 

 for treatment. 



Progress. Prolapse of the anus is usually reduced by laymen 



Fig. 422. — Prolapsus recti with invagination in the horse. 



without skilled assistance, and only when it continually recurs and 

 the mucous membrane becomes greatly swollen, or when it has 

 persisted for a long time, does it become the subject of skilled 

 treatment. Frey saw a horse which had difficulty in defaecation in 

 consequence of prolapse ; others have erroneously described chronic 

 prolapses as haemorrhoids. The mucous membrane undergoes change 

 from continued exposure to the air ; it becomes thickened, dry, necrotic, 

 and may slough, thus eventually bringing about spontaneous recovery 

 from the prolapse. Groll saw a pig with prolapse ; twenty days 

 later the protruded part sloughed away spontaneously, and recovery 

 followed, 



