300 



WALDO SHUMWAY 



III. Thyroid Emulsion III and Thymus Emulsion III were prepared from the 

 glands of nine rabbits killed and dissected April 25, kept in physiological salt 

 solution five hours, macerated, ground, and mixed one part to two parts boiled 

 tap water. These emulsions were kept in the refrigerator, and used in Experi- 

 ment 1, periods 13 to 15, and in Experiment 2, in the proportion 1-4 drop to four 

 drops 1-2 S.H.I. 



IV. Thyroid Emulsion IV and Thymus Emulsion IV were prepared from cow 

 thyroids furnished me by the kindness of Dr. Gudernatsch. On June 28 these 

 were macerated, ground and mixed one part to two parts boiled tap water and 

 used in Experiments 3 and 4, during periods 23 and 24, in the proportion 1-4 drop 

 to four drops 1-2 S.H.I. 



V. This symbol will be used for preparations made daily from Armour's Thy- 

 roids U.S. P. (desiccated) and Armour's Thymus (desiccated) by shaking up 1.5 

 mg. in 2 cc. boiled tap water and adding 2 cc. 1-2 S.H.I. Four drojjs of these 

 mixtures were used at each isolation. 



EXPERIMENTS 



Experiment I. April 9 to May 23, 1913. 



Average Division Rate 



For this experiment two lines of four files each were derived 

 from the control line (A), one of these (D) was kept in 1-2 S. H. 

 I. to which a small quantity of thyroid (Thyroid I, II, III, see 

 above) was added, the other (E), not shown on diagram 2, was 



Diagram 2 Chart showing life history of line A, together with the differences 

 produced in sub-lines treated with thyroid, some of which were thereafter re- 

 turned to control conditions. 



= Control line 



= Lines treated with thyroid 



-----= Lines returned to control conditions after thyroid treatment 



