Effect of Salts and Acids on Biocolloids and Cell-masses. 51 



matter retards and limits growth and development, or may have such 

 special effects as, for example, the condensation of chromatin into 

 special masses or chromosomes in the course of cell division. 1 Now, 

 protoplasm parallels the colloidal action of gelatine only in so far as it 

 is composed of protein or protein derivatives, and the proportions of 

 these substances and of the associated carbohydrates vary from organ 

 to organ and with the course of the seasons or the stage of develop- 

 ment. Furthermore, the biocolloids of the cell are acidified or salted, 

 and their behavior toward any reagent externally applied will of 

 course be determined or modified by all of the chemical and adsorptive 

 relations implied. Lastly, the residual acids of respiration vary from 

 hour to hour under ordinary circumstances. 



It might be expected, therefore, that tests which are planned to 

 determine the influence of acids or bases on growth would bring out a 

 diversity of results. 



G. A. Borowikow (Borovikov), a Russian working at the University 

 of Odessa, used seedlings of Helianthus 6 days old for testing the 

 effects of acids and salts upon growth. 2 The roots of the seedlings 

 were immersed in water and solutions in glass jars and the effects 

 upon growth derived from measurements of the length of the plant- 

 lets. Acceleration and final maxima were obtained by the use of 

 hydrochloric, sulphuric, nitric, acetic, and boric acids, in the order 

 named, that of hydrochloric being the greatest as compared with the 

 growth of plants in distilled water. It was also noted that the addi- 

 tion of salts to the acids influenced the rate and final effect, according 

 to the character of the base. Salts with weak, easily hydrolyzable 

 bases affected growth almost solely according to the concentration 

 of the hydrogen ions, but the stronger bases exercised a definite 

 effect, which in this author's work was to retard growth. It is clear 

 that the growing cell-masses of Helianthus are not identical in their 

 action with such amphoteric colloids as gelatine. 



Sections of growing internodes of Helianthus in my own work did 

 not show their greatest swelling in simple acid solutions, but in those 

 to which some salt of the same molecular concentration had been 

 added. It was also found that the hydration capacity of artificially 

 mixed biocolloids, dried and living sections of plants showed a decrease 

 in hydration capacity with rise in temperature above 16 to 18 C. in 

 acid solutions. On the other hand, it has been shown that in the 

 petiole of the calla (Richardia), which attains a length of over half 

 a meter and continues to elongate at varying rates throughout its 

 entire length, the greatest acidity is in the region of most rapid growth. 

 It is evident that interpretations must take into account a wider 



1 Mathews, A. P. Physiol. Chem., 2d ed., p. 235. 1916. 



2 Borowikow, G. A. Ueber die Ursachen des Wachstums der Pflanzen. Biochem. Zeitschr., 

 48:230, and 50: 119. 1913. 



