OBSERVATIONS ON CONTAMINATED WATER SUPPLY. 
329 
or two in proof. During the latter part of the summer of 
1890 1 had occasion to investigate a severe outbreak of dis¬ 
ease on a farm in one of the counties of Iowa. The animals, 
including horses, cattle and pigs, were all affected in the 
same way. The local symptoms were largely confined to the 
throat. There was a swelling, partial paralysis of the walls 
of the upper air passages, and painful and difficult breathing. 
The animals attacked uniformly died after an illness of about 
two days. The disease I could not recognize as belonging 
to any of the well defined types with which I was acquainted. 
Here were horses, cattle and pigs sick and dying with disease 
showing the same symptoms in all. There are few if any of 
the specific forms of disease that spread as epizootic among 
the widely differing species of domestic animals. I could 
not classify the disease, and at once set about the task of dis¬ 
covering, if possible, some common source of exposure. The 
pastures, buildings and water supply were each in turn sub¬ 
jected to careful scrutiny. The buildings were such as are 
to be found on ordinary Iowa farms, fairly comfortable and 
clean. 1 could find no clue in the quantity or quality of feed 
that promised to lead to a solution of the difficulty. On in¬ 
vestigation of the water supply, I found that most of the 
animals on the farm drank from a small cpeek that ran a zig¬ 
zag course through the premises. The stream was in part 
supplied from a series of springs, and in ordinary seasons af¬ 
forded a fair amount of water, which ran, at least for a por¬ 
tion of its course, over a gravelly bed. The present dry 
summer, with several previous ones showing an abnormally 
light rainfall, has so reduced the amount of water that it had 
ceased to run. On making examination and conducting in¬ 
quiries, I ascertained that it had been the custom on the farm 
to throw the carcasses of animals down the steep bluffs into 
the bed of the stream. I further learned that during the 
summer, chicken cholera had prevailed on the farm, and that 
a large number of chickens had died and been thrown over 
the bank. I was also informed that the hog cholera had 
caused the death of a considerable number of swine, the car¬ 
casses having been treated in a similar manner. The several 
