NINTH ANNUAL YEAR BOOK— PART VI 241 
At the request of Mr. McNeill, Dr. Niles gave a short outline of 
their work and its results: 
I might say that we have made so many experiments that we are per- 
fectly satisfied that the method is a success. There is no question about 
it. We worked this method out first in 1905. We had very little time and 
in 1906 we perfected it somewhat and made many experiments. We still 
wanted to try it in the field before we published anything about it. In 1907 
we manufactured some serum for the purpose of making tests. We sup- 
plied Mr. McNeill with some and also sent some to the Arkansas station, 
to Missouri and to Minnesota. Opportunity offered in the summer of mak- 
ing a pretty extended test in the field. We had a great deal of cholera 
in Story county and in Boone county and we found that there was so 
much of it there that we didn't have to. go far from home and we vac- 
cinated hogs on something like fifty different farms and started out to 
learn first as to whether we could prevent disease by vaccinating hogs 
before they were exposed if a neighbor's hogs were affected. We wished al- 
so to learn whether the farmer could be done any good after disease had 
gotten ihto his herd. Consequently v.e used our preparation in two kinds 
of herds, vaccinating a good many in which disease had appeared and a 
considerable number where disease had not appeared. In order to de- 
termine whether we did anything it was necessary to leave a good many 
check animals. Some of the herds we vaccinated very soon after the dis- 
ease appeared. In others disease had considerable start and in others a 
portion of the animals before exposure. Our expectations were fully 
met in the herds where disease had not started. A considerable num- 
ber of herds in which we vaccinated before the appearance of the disease 
showed by the checks that they had never become exposed, as the dis- 
ease did not appear in the checks. In a number of instances, however, 
the checked animals did get sick. Of course we went around the edge of 
the outbreak, not in a healthy section. In some of those herds the dis- 
ease appeared in the check animals and in most cases a great majority 
of the checks died and in some cases all. But in no instance did the vac- 
cinated hogs sicken. We made extended experiments on our own farm 
before we went out. Where disease had already appeared we were agree- 
ably surprised. I call to mind one herd in which we treated sixty-seven 
shoats. They were Duroc Jerseys weighing from twenty-five to seventy- 
five pounds. One shoat had been sick four or five days, another about one 
day and the disease was showing pretty plainly. We had to leave some 
animals untreated. We left twelve and treated sixty-seven. They all 
ran together and the two sick ones with them. Of the sixty-seven treated 
animals three died. The other sixty-four survived. Of the twelve animals 
not treated eight died and two others were decidedly sick. I am not 
able to say whether the remaining two showed any effect of the disease 
or not. I was some distance away and I was not able to visit it fre- 
quently. That is an illustration of what we did and what this method 
of vaccination will do in herds of this kind. We were very much sur- 
prised, as we did not know it would work out so well if there was disease 
in the herd. In herds where a larger number of sick animals were 
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