692 
W. L. WILLIAMS. 
In cases there appear, too, a well marked tendency to dis¬ 
ease of osseus tissue, not typical' of ordinary caries. In two 
cases without symptoms of caries I have seen in cases of poll- 
evil antero-posterior perforation of occipital protuberance with 
discharge of pus from the poll-evil escaping through this bony 
channel on the forehead. 
On the whole, poll-evil and fistulous withers in enzootic form 
like actinomycosis seem to be diseases of prairie localities and 
do not affect timbered regions. Of all states east of the Missis¬ 
sippi River, Illinois, the chief prairie state, seems the only one 
in which the prevalence of this disease cannot be accounted for 
satisfactorily on the traumatism theory. Dr. J. S. Butler, of 
Minneapolis, draws attention to a notable fact that in his 
region—as is the case in Illinois—the disease is rare in cities in 
comparison to the number of cases occurring on farms. Were 
traumatisms the sole cause such should not be the c‘ase. 
While many veterinarians of the west and northwest adhere 
to the general view that this disease has its sole cause in trau¬ 
matism, they admit its much greater prevalence and enzootic 
character, and quite a number in whose views I concur fully 
are thoroughly convinced that traumatisms do not cause a large 
percentage of the cases seen in the area where the disease is 
most common. Among these are Drs. Dinwiddie, Arkansas ; 
Lemay, Kansas; Stewart, Kansas, and T. J. Turner, Mis¬ 
souri. 
Periodic or Specific Opthalmia offers some very interesting 
facts in its geographical distribution. It seems common in the 
British Islands and continental Europe although not so preva¬ 
lent as in parts of the United States. In our country the disease 
occurs frequently in the New England and Atlantic States, due 
largely to importation from the Mississippi Valley. It appears 
to arise frequently in the Allegheny Mountains, and is reported 
common in Maine by Dr. Choate, and in Massachusetts by Dr. 
Paige. 
Along the coast it seems to disappear almost wholly, except 
as an imported disease, so Drs. Pearson, Peters, Kilbourne and 
