544 



WALDO SHUMWAY 



Race B' . Experiment 3. 



TABLE 14 



Division rate averaged by five day periods 



served that though the thyroid line shows a consistently higher 

 division rate than the control it was unable to survive the de- 

 pression period. 



TZp^ "^ 



Fig. 4 Graph showing comparative hfe histories of the thyroid fed and 

 control lines during Experiment B3 in average daily division rate re-averaged by 

 five day periods. Control , thyroid . 



Experiments were now begun in the hope of locaHzing the 

 factor to which the thyroid effect was due. Solutions of the 

 commercial iodothyrin were prepared in the same manner as the 

 glandular media. ■ Table 15 shows the division rates obtained 

 from the control, thyroid, and two iodothyrin Unes. It will be 



