From the above experiments it is seen that there is a direct paral- 
lelism between the per cent of iodine and the physiological activity 
of the thyroid. The thyroid of Group 5 (C) (from the dogs which 
had received iodoform and which contained 0.3 per cent iodine) 
enabled the mice to recover from about twice as much acetonitrile 
as did that from Group 2 (A) (normal, 0.111 per cent iodine). The 
thyroid of Group 4 (B) (potassium iodide fed dogs; 0.148 per cent 
iodine) was slightly more active than that of Group 2 and less active 
than that of Group 5. The amount of thyroid fed was compara- 
tively large, and in the case of Group 5 w^as probably greater than 
the minimum amount necessary to produce the maximum effect. 
Series II. 
In the following experiments different amounts of the thyroid 
were fed; in the first three the amounts were selected so as to make 
the total iodine about the same in all. 
A. THYROID OF GROUP 3 (NORMAL); 0.106 PER CENT IODINE. 
Date. 
Weight 
of mouse. 1 
Remarks. 
1908. 
April 14 
15.30 | 
Feeding of cakes each containing 0. 003 gm. thyroid commenced. 
17 
16.02 J 
20 
16.37 
22 
15.99 
Acetonitrile, 34.38 mgms., i. e., 2.15 mgms. per gm. mouse. Survived. 
April 14 
21.60 
Thyroid as above. 
17 
21.64 
20 
21.34 
22 
22. 10 
23 
22. 03 
Acetonitrile, 55.08 mgms., i. e., 2.5 mgms. per gm. mouse. Survived. 
April 14 
23. 58 
Thyroid as above. 
17 
24. 74 
20 
24 64 
23 
25.05 
Acetonitrile, 67.64 mgms., i. e., 2.7 mgms. per gm. mouse. Died one-half hour. 
April 14 
27.56 
Thyroid as above. 
17 
27.72 
20 
27. 50 
23 
28.30 
Acetonitrile, 89.9 mgms., i. e., 3 mgms. per gm. mouse. Died 2 hours. 
B. THYROID OF GROUP 4 (POTASSIUM IODIDE); 0.148 PER CENT IODINE. 
1908. 
L 14 
24 70 
17 
23.62 
20 
23. 57 
22 
22.70 
1 14 
19. 12 
17 
19.58 
20 
19.68 
23 
19.52 
1 14 
15. 10 
17 
16.14 
20 
16. 14 
23 
15.82 
114 
22.72 
17 
24. 32 
20 
24.92 
22 
25.32 
23 
25.50 
Feeding of cakes each containing 0. 002 gm. thyroid commenced. 
Acetonitrile, 56.75 mgms., i. e., 2.5 nigins. per gm. mouse. Survived. 
Thyroid as above. 
Acetonitrile, 50.75 mgms., i. e., 2.6 mgms. per gm. mouse. Survived. 
Thyroid as above. 
Acetonitrile, 45.88 mgms., i. e., 2.9 mgms. per gm. mouse. Survived. 
Thyroid as above. 
Acetonitrile, 73.95 mgms., i. e., 2.9 mgms. per gm. mouse. Died 1| hours. 
61494— Bull. 47—09 7 
