PROGRESS OF PROLAPSE OF THE ANUS. 
345 
Progress. Prolapse of the anus is usually reduced by laymen with¬ 
out 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 defecation 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 even slough, thus 
eventually bringing about spontaneous recovery from the prolapse. 
Fig. 155.—Prolapsus recti with invagination in the horse. 
Groll saw a pig with prolapse; twenty days later the protruded part 
sloughed away spontaneously, and recovery followed. 
The above is also true of prolapse of the rectum with invagination, 
except that as a rule defecation is difficult, the passage of material being- 
interfered with in the invaginated portion of bowel. The animals strain 
severely, causing further portions of intestine to protrude, these soon 
become cedematous, the folds in their mucous membrane disappear, and 
the surface of the prolapsed portion consequently appears smooth. The 
surface of the bowel, which is dirty and not infrequently injured by the 
animal rolling or lying, gradually becomes dry and presents a dark red 
or black colour. Pigs sometimes bite off the prolapsed portions in their 
fellows. 
