36 Hydration and Growth. 



Migrations of albuminous material from one part of the cell to 

 another and translocation of the proteins is a subject upon which 

 nearly all cytologists speak with great reserve because of the lack of 

 well-grounded observations. An extensive examination of such action 

 by the use of root-tips of Viciafaba has been made by Professor C. F. 

 Hottes, of the University of Illinois, and some of his results as yet 

 unpublished include facts of great possible importance. Dr. Hottes 

 says^ that seedlings deprived of the cotyledons and grown in the dark 

 at 20° C, being suppUed with nutrient salts and water, continued to 

 grow for a period of three days to a week. The changes in the nucleus 

 and the concomitant action of the cytoplasm during this time are very 

 striking in the root-tips. The nucleolus is enormously reduced in size 

 and its materials escape into the cytoplasm. Materials from distant 

 cells, albuminous in natxire, are transported . through considerable 

 distance to the meristem of the tip, and these cells remain aUve, sustain- 

 ing a parasitic relation to the cells from which the material has been 

 derived, and the fundaments of lateral roots are broken down and 

 translocated in the same manner. The progress of the translocation 

 may be followed through the strands connecting with the tip meristem. 

 Such transfer of materials is apparently inhibited at low and high 

 temperatures which lessen or stop growth. Antipyrine accelerates 

 exudation and transfer of such proteinaceous material and chloral 

 hydrate inhibits it. Furthermore: 



" In all treatments leading to inhibition of cell activity, I find enlargements 

 of nucleolus, increase of chromatin without the passage of perceptible amounts 

 of these materials into the cytoplasm. In cell acceleration the nucleolar 

 material can be distinctly followed through the reticulum of the nucleus into 

 the cytoplasm. The chromatin (tropochromata) fluctuates in quantity and 

 its increase and decrease is concomitant with the absence and presence of 

 chromatin (chromidia) in the cjrtoplasm." 



As the proteins diffuse sparingly,^ their translocation ia living mat- 

 ter must take place by some other method, and one by which a rela- 

 tively rapid movement would be possible. So far as plants are con- 

 cerned, the possibiUties offered by the amino-acids may prove to be 

 of the greatest importance in this connection. These substances pass 

 through membranes, show a relatively high rate of diffusion, and are 

 readily derived and combined. 



' Letter to author. 



' Robertson, T. B. The physical chemistry of proteins. New York. 1918. See p. 330. 



