43 
This chart shows that the highest death rate for 
Psittaci is to be expected in May, August and December 
while deaths from pro ventricular worms show the highest 
percentages in April, May, July, August, September and 
October. Generally speaking, spring and late summer 
show more deaths from worms than other periods. 
Against these statistics the clinical picture may be 
adduced. 
Most of the birds infested are parrots, but toucans, 
pigeons and several other isolated families have been 
affected. The worm has been described by Dr. Allen J. 
Smith and named Spiroptera incerta.^ The mature 
female averages 14 Mm. in length, but a solitary female 
from a Senegal parrot measured 25 Mm. (1 inch). This 
female was accompanied by a solitary male. These 
worms vary in numbers from two to a hundred or more. 
The largest ones are found either in a ball of mucus 
occupying the lumen of the proventricle or imbedded 
in its mucosa. A case was recently posted where the 
worm was coiled under the serosa, indicating that the 
worm has considerable powers of penetration. The 
smallest worms are found under the thick chitinous 
lining of the gizzard. 
Several things would indicate that the worm may 
cause death and is not always a harmless commensal. 
The birds are emaciated. In the second place micro- 
scopic sections discover marked destruction of the pro- 
ventricular mucosa, which is the essential gastric struc- 
ture of birds. In fact it has been named the glandular 
stomach, in contradiction to the gizzard or muscular 
stomach. Again there is much swelling and distention 
of the viscus by mucus, giving the possiblity of obstruc- 
tion to the ingestion of food. In one case, that of a 
love bird, the swelling was so extreme as to push the 
heart over into the right half of the body. In another 
case an unmistakable perineurial round cell infiltrate in 
* Allen J. Smith: Synopsis of Studies in Metozoan Parasitology — Uni- 
versity of Pennsylvania Medical Bulletin, February, 1908. 
