EXPERIMENTS WITH TUBERCULIN ON NONTUBERCULOUS COWS. 
129 
system was charged with this second last injection. This low 
record could not be justly charged on the tuberculin injection 
seeing that it was already reached the day before that injection. 
Daisy like the rest of the herd was falling off in milk during 
the experiment, and her average when charged with tuberculin 
suffers on account of her having reached her lowest mark on 
December 7th, on the evening on which a dose of tuberculin was 
given, and further, that on December 13th, the day of the last 
test her milk shrunk because she was in heat. Taking the seven 
tests the arrays stand thus : Average of the seven days follow¬ 
ing the injections of tuberculin 17.82 lbs. Average of the forty- 
seven days for which the milk record is given 18.26 lbs. This 
shows a difference of less than half a pound daily on the average 
against the tuberculin. If we leave out the last injection (Decem¬ 
ber 13th) when the cow was in heat, we find that the average 
yield per diem for the next six days during which the cow was 
charged with tuberculin is slightly above the average for the 
whole forty-seven days of the trial. 
Molly , Freda and Bertha. These cows were not injected 
with tuberculin, and their milk records have been introduced 
to show that the daily oscilations in the yield, and its progressive 
diminution in the main during the forty-seven days, was common 
to the whole herd, and in no sense peculiar to the three cows 
that had been treated with tuberculin. The gradual failure can 
be seen in the tables. It may be more clearly shown by placing 
side by side the general average for the first four weeks, and the 
average for the last two weeks and five days. 
Average for first twenty-eight days, 
BELVA 
MOLLY 
FREDA 
DAISY 
BERTHA. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
38.10 
4 I - 3 I 
43 * 5 1 
• 
19.23 
28.46 
Average for the last nineteen days, 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
36.00 
42.87 
40.51 
16.76 
26.13 
2.10 
1.56 
3.00 
2.47 
2-33 
