65 
F. SHEEP THYROID; 0.19 PER CENT IODINE. 
Date. 
Weight of 
mouse. 
Remarks. 
1908. 
April 8 
12. 02 
Feeding of cakes each containing 0.001 gm. thyroid commenced. 
11 
12.00 
14 
11.80 
16 
11.11 
Acetonitrile, 42.22 mgms., i. e., 3.8 mgms. per gm. mouse. Survived. 
April 8 
*14. 37 
Thyroid as above. 
11 
14.08 
14 
13.74 
16 
12.90 
Acetonitrile, 56.76 mgms., i. e., 4.4 mgms. per gm. mouse. Survived. 
April 8 
13.08 
Thyroid as above. 
11 
13. 14 
14 
13.36 
16 
13. 52 
17 
12. 94 
Acetonitrile, 62.11 mgms., i. e., 4.8 mgms. per gm. mouse. Died 2J hours 
SUMMARY. 
Gm. 
thyroid 
fed daily. 
Percent- 
age of 
iodine in 
thyroid. 
Mgm. I in 
thyroid 
fed daily. 
Fatal dose of aceto- 
nitrile in mgms. 
per gm. 
Recovered. 
Died. 
A 
0. 001 
0.11 
0. 0011 
2.5 
3.0 
A* 
.002 
.11 
.0022 
4.1 
4.6 
B 
.001 
.13 
.0013 
2.8 
2.7 
C 
.001 
.13 
.0013 
2.9 
3.1 
D 
.001 
.10 
.0010 
3.8 
D 1 
.002 
.10 
.0020 
3.8 
3.9 
E 
.001 
.19 
.0019 
4.7 
4.6 
F 
.001 
.19 
.0019 
4.4 
4.8 
In the above series the physiological activity of thyroid contain- 
* ing 0.11, 0.13 (two samples), 0.10, and 0.19 per cent (two samples) of 
iodine was compared; the preparations were from different manu- 
facturers and were received at different times. Three of the samples 
with the lower percentages of iodine produced approximately equal 
effects. The two samples with the higher percentages also pro- 
duced equal effects; the latter were nearly twice as great as those 
produced by the former. Moreover, one of the weaker preparations, 
in twice the amount, produced an effect about equal to that of one 
of the stronger ones. We encountered in this series one of the few 
exceptions to the general rule that the physiological activity of a 
thyroid preparation is parallel to the iodine content. The prepara- 
tion D, containing 0.1 per cent iodine, was as active as E and F, 
which contained 0.19 per cent iodine. Possibly there was some 
error in the weighing of the thyroid or the making of the cakes. In 
an earlier series with the same preparations the ones with the larger 
percentages of iodine were about twice as active as the one with the 
smaller percentage of iodine. 
61494— Bull. 47—09 5 
