THE ANIMAL PARASITES 641 
The toucans and other species, being housed elsewhere, 
were not quarantined. Following this, we were grati£ed 
to experience no more spiroptera deaths in parrots for 
seven years. Then, in 1920 and 1921, a new outbreak 
occurred in four toucans and several other scattering 
species, including two parrots; but none of these came 
from the main parrot house and probably represented a 
fresh importation. We attempted to cure the isolated 
verminous birds by medication but were unsuccessful. 
Likewise attempts at determining the life-cycle of the 
parasite brought us no farther than that the ova devel- 
oped larvae in moist sand in six days. Feeding of ova, 
freshly passed and larvated did not produce infestment 
in parrots or pigeons. On the whole we can quote our 
experience with spiroptera as a most satisfactory exam- 
ple of the value of hygiene and as a result which could 
never have been accomplished by medication. 
Hepattcola (Trichosoma)Hepatica in Pratkie Dogs. 
Bancroft (23) and Hall (24) have given us details con- 
cerning this parasite and the disease it causes. It is 
threadlike, several inches long, and permeates the livers of 
the gray rat, white rat and wild hare. (25) We first saw it 
in the more or less cirrhotic livers of several prairie dogs ; 
later we observed it in a beaver and the gray rats of 
the Garden. In the prairie dogs and beaver the liver 
resembled that of fatty cirrhosis and was so considered 
on naked eye examination at our first autopsy. We 
were only set right when we came to the histological 
examination. It was remarkable how well conditioned 
some of the prairie dogs were in in the face of very exten- 
sive liver destruction ; but on the other hand some were 
emaciated and a few of the spontaneously diseased showed 
at autopsy an enormous ascites. The outstanding features 
at autopsy were the large size of the liver and its pallor 
(23) Proc. Roy. 8oe. N. So. Wales, Sydney, Vol. 27, pp. 86-90 1893 
(24) Proc. U. S. Nat. Mus., Wash., D. C, Vol. 50, 1916, p 31 
(25) Proc. Zool. Soc. London, 1911, p. 674. 
