ARSENICAL POISONING FROM SMELTER SMOKE. 
307 
inestimable advantage in being- able to protect itself from the 
prolonged action of an irritant, at the point corresponding to that 
where the ulcer develops in the horse, by easily inserting its 
tongue into the nostril and removing the irritating material. It 
is to these peculiarities of bovine animals that the writer attributes 
their exemption from the nasal ulcerations. 
The sheep, which resembles more nearly the horse in its 
manner of biting the grass, and in the sensitiveness of the skin 
and mucous membrane of the nose, is not exempt from the 
ulcerations, though from their smaller size in this animal the 
ulcers are not so conspicuous. Dr. Formad, who made an inves¬ 
tigation on behalf of the U. S. Bureau of Animal Industry, has 
given a very conclusive illustration, from a photograph, of such 
an ulcer in a sheep’s nostril, and states that out of a flock of 60, 
pastured about ten miles north of the smelter, io were examined, 
and 3 of these had nasal ulcers.(io) 
The writer, also, saw these ulcers in sheep and made a record 
of the examination of 4 of these animals on the Para ranch, De¬ 
cember 5, 1906, of which 3 had ulcers in their nostrils very simi¬ 
lar to those of horses, and these were covered by soft black crusts. 
Horses, therefore, are not the only animals which suffer from 
the “ sore noses,” and the fact that cattle do not exhibit such 
lesions cannot be accepted as valid evidence against the arsenical 
theory. 
To recapitulate: 
The “ sore noses ” or nasal ulcerations of the horses of the 
Deer Lodge Valley do not appear in the summer or fall until two 
or three weeks, or longer, after the smoke has been over the 
valley. 
They are not inoculable. 
They begin to heal at once if the horses are removed from the 
pastures' and fed on arsenic-free hay. 
They are not transmitted by cohabitation. 
Similar “ sore noses ” have been observed in horses around 
other copper smelters. 
The nasal mucous membrane of horses at pasture, at the time 
