NINTH ANNUAL YEAR BOOK— PART III 103 
In reporting results of practical tests of serum made, he says, "con- 
cerning protective power of serum from hyper-immunized immunes are 
based upon tests upon several thousand hogs. These tests were not car- 
ried out in small experiment pens, but in great part upon practical con- 
ditions. During the fall of 1907, approximately two thousand hogs were 
treated on fifty different farms, a considerable portion of untreated hogs 
being left in all cases as a control on the action of the serum. Both 
methods of vaccination were used and the herd conditions varied widely. 
The herds can be roughly classified as (A), those in an infected local- 
ity but themselves free from disease; (B), those which were known to 
have been exposed by contact with sick hogs, but which had not developed 
the disease at the time of treatment, and (C), herds in which hog cholera 
was present and hogs sick and dying at the time of treatment. In no 
case were any of the ordinary methods of combatting hog cholera by dis- 
infections and separation of the sick from the apparently healthy prac- 
ticed. Where disease was present at the time of treatment, the treated 
were allowed to run with the sick animals along with a number of un- 
treated animals, which served as controls; and the success following 
vaccination can, therefore, be attributed to the action of the serum. In 
herds where hog cholera appeared supsequent to treatment, all the vacci- 
nated hogs remained well, while more than 65 per cent of the checks or 
untreated ones died. 
In the herds which had been exposed, as in class (C), but were appar- 
ently well at the time of treatment, four per cent of the treated animals 
died when approximately 90 per per cent of the checks succumbed. In the 
herds in class (C), where this disease existed at the time of treatment 
and where they did not anticipate very great success, 13 per cent of the 
treated animals were lost where 75 per cent of the checks died. 
These successful field trials, confirming as they did numerous tests 
carried out under experimental conditions, have convinced us of the effi- 
ciency of this method of dealing with hog cholera, and although improve- 
ments will undoubtedly be made in many other details of producing this* 
serum, the methord is believed to be now in such condition as to make 
the practical use of it entirely feasible. 
While my experiments have been limited with the serum, yet with the 
good results I have obtained and those reported by the bureau I have 
every reason to believe of its practicability. At the present time the 
great drawback to universal use of this serum is the almost prohibitive 
high price at which it is sold. 
The price charged by those putting it on the market at the present 
time is $1.00 per twenty c. c, which would be a dose for a hog weighing 
from seventy-five to one hundred pounds, or $3.00 for one weighing three 
hundred pounds. 
Michigan has begun the preparation of this serum, so I am informed, 
for the distribution to the farmers of that state at two cents per c. c, or 
forty cents per dose, which is sufficient for a hog of about one hundred 
pounds, but they hope to reduce the price materially before another season. 
Dr. Melvin thinks that if he serum station would be under the control 
of the state, and with the production carried out with strict economy it 
could be brought down to twenty-five cents per dose. This statement is 
