218 DISEASE IN WILD MAMMALS AND BIRDS 
Rectal Peolapse. 
Prolapse of the rectum may in a sense be looked upon 
as a hernia or at least as a relaxation of the anal and 
perineal muscles with protrusion of parts normally situ- 
ated intracorporeally. Although not frequent it has been 
incurable in the animal, as it frequently is in man without 
operation, a measure we have not adopted. Just what 
determines weakness in the pelvic outlet is entirely 
obscure for indeed we have seen here wounds and inflam- 
mations of the perineal area without prolapse of the 
rectum and in none of the cases of prolapse did the pelvic 
floor seem injured or diseased. It is but speculation to 
blame the annular muscles of the anus. Tenesmus, or at 
least reasons for this straining action, have been sought, 
with the result that in our cases lesions of the egg-laying 
apparatus in birds and enteritis in mammals have stood 
out most prominently. In no case have hemorrhoids been 
encountered nor has a tumor pendant from the colonic 
mucosa, drawn the bowel toward the anal opening. It 
might be added parenthetically here that hemorrhoids are 
practically unknown for quadrupeds, Hutyra and Marek 
failing to mention them independently and only one refer- 
ence being found in the Jahresbericht fur Veterindr 
Medizin (Schmidt 1914-169); this case is more like 
angioma than hemorrhoids. If tenesmus be active in the 
production of rectal prolapse then it would have to be 
assumed that this straining effort can be induced by enter- 
itis since eversion of the rectum has occurred with this 
disease in the absence of colitis, the condition usually 
expected in the presence of tenesmus. The thirteen cases 
have been seen in Mammalia, 8, (Carnivora, 2, Rodentia, 1, 
Ungulata, 3, Edentata, 1, Marsupialia, 1) and Aves, 5, 
(Passeres, Picariae, Striges, Psittaci and Galli each one). 
Three mammals had enteritis, one had foreign bodies in 
the bowel and one had many ascarids; three had no 
demonstrable or suggestive causes. Two of the five birds 
