6 
Part I. The parallelism between the physiological activity and the 
iodine content of thyroid — Continued. 
B. Experimental — Continued. 
Methods, effect of feeding thyroid upon the susceptibility of animals 
to various poisons. Advantages of the method — Continued. 
1. Experiments with acetonitrile — Continued. Page. 
b. Experiments on rats 72 
Thyroid lowers the resistance of rats to acetonitrile. 
Parallelism between the iodine content and the 
physiological activity. General conclusions. 
2. Experiments with morphine 77 
Introduction. Resistance of rats, mice, and guinea pigs 
to morphine diminished by feeding of thyroid. 
a. Experiments on white rats 78 
Parallelism between physiological activity and iodine 
content of thyroid preparations. 
b. Experiments on mice 85 
c. Experiments on guinea pigs 87 
Conclusions from the experiments with morphine 90 
Explanation of effects of thyroid upon resistance to 
morphine. Possible clinical bearings. 
Part II. On the nature op the relation between the iodine percentage 
AND THE PHYSIOLOGICAL ACTIVITY OF THYROID 93 
Historical: Roos’s experiments on the activity of thyroid the iodine con- 
tent of which was increased by the administration of potassium iodide. 
Discussion of Roos’s results. 
Experimental demonstration that the activity of thyroid iodized in vivo is 
increased in proportion to the increased iodine content. 
1. Experiments with acetonitrile — 
a. Experiments on mice 95, 110 
b. Experiments on rats 103 
2. Experiments with morphine — 
a. Experiments on mice 106 
b. Experiments on rats 107 
Bearing of the results on the question whether there is a 
casual relation between the iodine content and the 
physiological activity. 
