ROBERT A. BUDINGTON. 



of the nutrient fluid; supra-renal gland tablets were also used, 

 in strengths of i, 0.75, 0.5 and 0.25 grains in 120 c.c. of nutrient 

 fluid; but there was no uniform effect of these substances, the 

 appearance being that these substances so used have no influence 

 at all on this particular plant tissue. 



SUMMARY. 



1. Growth of root-tips of A Ilium is retarded by the presence 

 in their fluid nutrient environment of thyroid gland material. 

 Retardation is approximately in direct proportion to the amount 

 of thyroid substance present. 



2. The presence of thyroid materials in the nutrient fluid in 

 which Allium is sprouting does not modify the growth of the 

 early leaves. 



3. Iodine, used as KI, in amounts equivalent to that in thyroid 

 substances provoking marked modifications of growth, has no 

 appreciable effect on growing root-tips. 



4. Pituitary substances up to two grains of the desiccated 

 gland, and supra-renal substances up to one grain of the desic- 

 cated gland in 120 c.c. of nutritive solution have no effect on the 

 growing root-tips of Allium. 



5. While no general conclusion can be based on experiments 

 limited to a single form, the indication is that thyroid constituents 

 may influence the role of protoplasmic action in cells other than 

 those of animal tissues. 



LITERATURE. 

 Budington, R. A., and Harvey, H. F. 



'15 Division Rate in Ciliate Protozoa as Influenced by Thyroid Constituents. 



BIOL. BULL., 28, 304-314. 

 Chambers, Mary H. 



'19 The Effect of some Food Hormones and Glandular Products on the Rate 



of Growth of Paramecium caudatum. BIOL. BULL., 36, 82-91. 

 Curtis, Otis F. 



'18 Stimulation of Root Growth in Cuttings by Treatment with Chemical 



Compounds. Cornell Univ. Agr. Exp. Sta., Memoir 14, 71-138. 

 Kunkel, B. W. 



'18 The Effects of the Ductless Glands on the Development of the Flesh Flies. 



Jour. Exper. Zool., 26, 255-264. 

 Marine, D., and Lenhart, C. H. 



'09 Relation of lodin to the Structure of Human Thyroids. Arch. Inter. Med., 

 4. 440-4Q3- 



