Protozoan Ictero-hcematuria in sheep, etc. 621 



the blood and the structural lesions supported the idea of identity. 

 Altitude seems to have little or no effect as a causative factor, 

 as the disease is domiciled alike on the low alluvium of the 

 Danube and the Deer L,odge Valley of Montana over 5,000 feet 

 above the ocean. In both regions there is the common condition 

 of inundation or its equivalent irrigation, for the Montana range 

 is dry and arid, interspersed with alkaline bogs inimical to vege- 

 tation, but prolific and fruitful under irrigation. The Montana 

 disease has been attributed to mineral poisons carried on the 

 winds from the extensive copper smelters in Butte and Anaconda, 

 but the smelters had been in existence for eight or ten years be- 

 fore this disease was observed, and from its appearance the infec- 

 tion has gradually extended, attacking sheep only, and sparing 

 other domestic animals, which would have suffered as well 

 from a mere mineral poison on the vegetation. The doctrine 

 of a mineral poison is equally contradicted by the habitual preva- 

 lence of the disease in spring and autumn, while it is dormant 

 in winter and summer. In winter the flocks eat hay cut from 

 the richer valley lands and meadows, while in summer they are 

 pastured on the foothills and mountains, and drink from the 

 mountain springs surrounded by alkaline bogs. The autumn 

 outbreak occurs long after the mountain grasses have dried up, 

 when the flocks are thrown back on the supplies obtained from 

 the alkaline bogs and the valley pastures. In late winter and 

 early spring the growth naturally starts first in the same boggy 

 and valley areas, and both facts suggest a microbian infection — 

 protozoan or bacterian. A vegetable poison would better accord 

 with the conditions (See Cirrhosis of the lyiver from Senecio. 

 Vol. II.; If an intermediate host or bearer — insect or other 

 invertebrate — is to be assumed it implies two. generations 

 of these, a spring and an autumn one, in the same season, 

 or otherwise a restriction of such invertebrate to the low val- 

 ley pastures and the alkaline bogs on the higher levels, and 

 that they disappear from the drier, arid areas in summer. It 

 cannot be an obligate parasite like a louse or melophagus which 

 would be constantly present, nor a musquito absent in early 

 spring. But up to the present no invertebrate host or intermedi- 

 ate bearer has been identified. Cases were at first reported in 

 the Angora: goat, but this animal is now known to be immune. 



