386 



Scientific Proceedings (131) 



186 (2146) 



The effect of thyroid products on Paramecium. 

 By LORANDE LOSS WOODRUFF and WILBUR W. SWINGLE. 



[From the Osborn Zoological Laboratory, Yale University, 

 New Haven, Conn.] 



Studies of Nowikoff, Shumway, and Budington and Harvey 

 on the influence of thyroid products on Paramecium have appar- 

 ently shown a marked increase in the rate of reproduction, and 

 their results have been generally cited as a corroboration of the 

 view that the active principle of the thyroid directly accelerates 

 cell metabolism. 1 Recently Riddle and Torrey have failed to 

 find an increased reproduction in Paramecium following sub- 

 jection to thyroxin. 2 



We have reinvestigated the influence of thyroid products by 

 a series of experiments on a pedigree race of Paramecium, using 

 the organism as a "biological indicator" and following the gen- 

 eral technique employed in other studies on Paramecium 

 in this laboratory. 3 



The results, which will be published in detail elsewhere, 4 show 

 in a clear cut manner that neither thyroxin (Squibb's) nor com- 

 mercial dessicated thyroid, or fresh dessicated thyroid of the tur- 

 tle produce any significant acceleration of the division rate of 

 Paramecium. 



Data to the contrary published by previous investigators ap- 

 parently are attributable chiefly to variations in the bacterial 

 food supply which the different media afforded the Paramecia. 



Accordingly, all the evidence from studies on Paramecium to 

 the effect that thyroid products accelerate cell anabolism is, we 

 believe, erroneous. 



1 Nowikoff , M., Arch. f. Protistcnlcundc, 1908, xi ; Shumway, W., Jour. 

 Exper. Zool, 1914, xvii; Ibid., 193 7, xxii; Budington, K. A., and Harvey, 

 H. P., Biol. Bull, 1915, xxviii. 



2 Kiddle, M. C, and Torrey, H. B., Proc. Amcr. Soc. Zool., Anat. Rec, 

 1923, xxiv. 



8 Woodruff, L. L., Biochcm. Bull, 1912, i; Woodruff, L. L., and Under- 

 bill, F. P., Jour. Biol Chcm., 1913, xv. 

 * Journal of Biological Chemistry. 



