170 
D. E. SALMON. 
now be examined in the light of such further evidence as is avail¬ 
able. 
i. Have similar lesions been observed in the neighborhood 
of other smelters —Harkins and Swain(i) observed similar 
nasal ulcers in the vicinity of the Salt Lake smelters, and as they 
had examined many of these lesions in the Deer Lodge Valley, 
there can be no question of their competency to decide as to the 
similarity of the process. They further state, without giving 
their authority, that these ulcers have been reported from the 
district about the Great Falls smelter, and, also, from the smelt¬ 
ing region in Cornwall. The writer has not been able to make 
any personal investigations in regard to this question. 
2. Docs the dust deposited from the smoke of the Washoe 
smelter produce irritation of the skin and mucous membranes 
when applied thereto ? Here, again, the observations of Harkins 
and Swain must be referred to.(2) They say: 
“Of the persons who worked on the smelter stacks in deter¬ 
mining the arsenic content of the smoke, two became affected 
with an arsenical rash on the face, while the nostrils of the third 
were almost closed by a swelling caused by the irritant action of 
the flue dust.” 
They say with reference to thresher dust: 
“ Complaints are often made by men working on these 
machines that the thresher dust from grain in the smoke zone 
irritates the skin and the mucous membranes of the eves and nasal 
j 
passages.” (3) 
The writer frequently heard similar complaints from men 
engaged in threshing, and in some cases, it was said, sores would 
form on the parts of the body where the perspiration was abun¬ 
dant. It was difficult for this reason to get men to do the thresh¬ 
ing on ranches where there was a heavy deposit of dust. 
3. What are the conditions under which the nasal ulcers of 
the horses are produced ?—Examining the horses at pasture at 
the time the ulcers were beginning and afterwtards, it was ob¬ 
served that, generally, the interior of the nostril was covered 
with a thin layer of grayish-black material, which sometimes was 
