PROGNOSIS AND TREATMENT OF ATRESIA ANI. 
837 
In the latter case the animal may live, provided the ano-vaginal 
opening is large enough to allow discharge of bowel contents. 
Burmeister saw an ano-vaginal fistula of the size of a straw in a 
six weeks pig. Pieperbrok found recto-vaginal fistula and imperfoiate 
anus in a pregnant sow. 
In atresia ani or recti the animals sooner or later die, if provision be 
not made by operation for discharge of excrement, though, as the milk 
forms comparatively little faeces, the animals may continue to live foi 
several weeks. Atresia ani was seen by Waltrup in a twenty-six days 
sucking pig, and by Moller in a puppy of the same age. Buminants 
seldom live so long; in them severe disturbance results from suppressed 
defecation after four to eight days; in a case described by Bull, a calf 
lived five days *. the post-mortem showed the walls of the rectum adheient 
for a distance of 5 to 6 inches. 
Prognosis is in general favourable, provided operation is not too long 
deferred. It depends principally on whether the anus alone or both anus 
and a considerable piece of rectum are simultaneously closed ; in the 
latter case there is always great difficulty in laying open the bowel, and 
in keeping it patent. The artificial anus tends strongly to contract and 
interfere with defecation, whilst the rectum becomes paralysed on 
account of severe distension, and may even be ruptured; in such case 
operation gives no relief. In man, clysters of tobacco smoke have been 
used, and may be tried in animals. Where they fail eserine may be 
given, though in cautious doses if the animals are already weak. 
& Treatment. Operation is the sole resource. Some recommend delaying 
it for a day or two after birth, because moderate distension of the rectum 
is rather advantageous, but as a rule the surgeon’s attention is not 
demanded at this time, often not till much later, when death is unavoid¬ 
able. In atresia ani the anus is only closed by a layer of skin which is 
simply grasped with forceps and cut through with the scissois. Fasces 
are usually discharged at once : if not, the subcutaneous tissue, which 
sometimes contributes to the obstruction, must be thrust on one side. 
Beunion of the edges may generally be prevented by smearing the parts 
with some mild ointment. For a similar purpose the mucous mem¬ 
brane of the rectum is in man united with the outer skm by in¬ 
cising the skin from above downwards right over the anus, dividing 
the subcutis on either side of the projecting end of the lecturn, cutting 
through the mucous membrane in the same direction, and uniting it 
with the outer skin by several interrupted sutures. Stenosis is thus 
prevented. 
The operation for atresia recti is more difficult, paiticulaily if the 
rectum is extensively adherent to neighbouring parts. I he less piomi- 
nent the anus from pressure of bowel contents, the moie unfavouiable 
