Southern cattlemen bought northern cattle; they were unloaded from their box-cars and put to graze on the fields along with perfectly healthy southern cows; everything would go well for a month or so, and then, bang! an epidemic burst out among northern cows. They stopped eating, they lost dozens of pounds a day, their urine ran strangely red, they stood aimless with arched backs and sad eyes--and in a few days every last one of the fine northern herd lay stiff-legged on the field. The same thing happened when southern steers and heifers were shipped North; they were put into northern fields, grazed there awhile, were driven away perhaps; when northern cows were turned into those fields where their southern sisters had been, in thirty days or so they began to die--in ten days after that a whole fine herd might be under the ground. What was this strange death, brought from the South by cattle never sick with it themselves, and left invisibly in ambush on the fields? Why did it take more than a month for those fields to become dangerous? Why were they only dangerous in the hot summer months? The whole country was excited about it; there was bad feeling between the meridional cowmen and their colleagues of the North; New York City went into a panic when carloads of stock shipped East for beef began to die in hundreds on the trains. Something must be done! And the distinguished doctors of the Metropolitan Health Board went to work to try to find the microbe cause of the disease.... Meanwhile certain wise old Western cattle growers had a theory--it was just what you would call a plain hunch got from smoking their pipes over disastrous losses of cows--they had a notion that Texas fever was caused by an insect living on the cattle and sucking blood; this bug they called a _tick_. The learned doctors of the Metropolitan Board and all of the distinguished horse doctors of the various state Experiment Stations laughed. Ticks cause disease! Any insect cause disease! It was unheard of. It was against all science. It was silly! “... A little thought should have satisfied any one of the absurdity of this idea,” pronounced the noted authority, Gamgee. This man was up to his nose in the study of Texas fever, and never mentioned a tick; the scientists all over gravely cut up the carcasses of cows and discovered bacilli there (but never saw a tick). “It is the dung spreads it!” said one. “You are wrong, it is the saliva!” said another. There were as many theories as there were scientists. And the cattle kept on dying. IV