30 
B. CONTROLS. 
Date. 
Weight of 
mouse. 
Remarks. 
1908. 
February 1 
18.83 
Feeding of cakes without iodothyrine. 
4.... 
20. 01 
7.... 
20. 19 
10.... 
19.02 
Acetonitrile, 4.76 mgms., i. e., 0.25 mgm. per gm. mouse. Survived. 
February 1 — 
16.49 
Cakes as above. 
4.... 
15. 56 
7.... 
15. 79 
10.... 
16. 31 
Acetonitrile, 4.24 mgms., i. e., 0.26 mgm. per gm. mouse. Died 10 hours. 
Summary. — 0.005 gm. of the milk sugar trituration was fed; this 
mixture contained only 1 part of the true iodothyrine in 310. Hence 
there was fed daily but 0.0161 mgm. iodothyrine. The results are 
summarized in the following table: 
Mgm. true 
iodothyrine 
fed daily. 
Mgm. I in 
true iodo- 
thyrine. 
Weight of 
mouse in 
gms. 
Amount of acetonitrile 
in mgms. 
Result. 
Per mouse. 
Per gm. 
mouse. 
A 
0. 0161 
0. 00000225 
17. 30 
43. 25 
2.5 
Recovered. 
.0161 
. 00000225 
19. 07 
49. 58 
2. 6 
Died. 
B 
0 
0 
19.02 
4. 76 
! 25 
Recovered. 
0 
0 
16.31 
4.24 
.26 
Died. 
Thus a mouse (A) which had received iodothyrine recovered from 
nearly ten times the relative amount of acetonitrile fatal to the controls. 
Since 0.25 mgm. per gram is the maximum amount of acetonitrile from 
which a control (B) recovered, we are justified in assuming that this 
represents the maximum amount of the poison which a mouse of this 
series could, under normal conditions, neutralize; for a mouse weigh- 
ing 17.30 gms. (A) this' would be a total of 4.33 mgms. The mouse 
which weighed 17.30 gms. and which had received iodothyrine recov- 
ered, however, from 43.25 mgms. Hence we may conclude that the 
iodothyrine had enabled the mouse to resist in some way the poisonous 
effects of 38.92 mgms. acetonitrile. The total amount of iodothyrine 
which the mouse had received in ten days was somewhat less than 
0.161 mgm. Thus one part of true iodothyrine fed to a mouse in the 
course of ten days had enabled it to resist more than 240 times an 
equal weight of acetonitrile. 
Although we speak of the poison being “ neutralized’ 7 wdien a 
mouse, , as a result of the administration of thyroid, recovers from 
several times the fatal dose of acetonitrile, it is very probable that 
there has been no neutralization whatever. The effect is probably a 
preventive one — that is, the thyroid in some way prevents the forma- 
tion of a poison from the nitrile. The basis of this suggestion is the 
fact that the feeding of thyroid has no effect upon the toxicity of 
