42 Proceedings of Indiana Academy of Science 



obscure. The quick movement of cilia after a stimulus shows its rapid 

 propagation. 



Physiologists differ as to the origin of excentric growth in roots 

 and branches (11). The question of annual rings still awaits a solu- 

 tion (1, Bd. II, p. 274) along with certain ribbon shaped stems (11). 

 On the subject of osmosis and plasmolysis, various questions remain 

 for solution. How does a diatom retain its form in spite of the internal 

 hydrostatic pressure (1, Bd. I, p. 122)? In the case of plants whose 

 roots have been killed by heat the stems may remain living for several 

 days but no experiments have as yet been made on their transpirational 

 behavior. I*Jo exact work has been done to ascertain the influence of 

 external agencies on the excretion of water pores. Similarly, doubt 

 still surrounds the methods of sugar secretion by glandular cells and 

 the means by which gland cells escape injury by high osmotic forces 

 (1, Bd. I, p. 265) and other factors notwithstanding the large amount 

 of excellent work that has been done on the subject. 



The objections to the plasmolytic method are negatived in as much 

 as verification of the method is easily obtained in various ways. Ost- 

 wald (23) has given an illustration of the membrane concerned and 

 osmotic pressure in a theoretical way. The cryoscopic and other meth- 

 ods give results of great value. De Vries used the plasmolytic method 

 to determine the molecular weight of raffinose and his results have since 

 been confirmed (24). Moreover the work of Pfeff"er has been confirmed 

 again recently by Morse (25) and others who have made notable con- 

 tributions to the subject. Among these the work of Fitting and Renner 

 may be mentioned. Various questions arise concerning the conditions, 

 under which natural plasmolysis occurs. Although a new cell wall may 

 sometimes form around a plasmolysed cell which may remain living 

 from a few hours to several weeks, nevertheless permanent plasmolysis 

 produced and maintained aitificially always finally causes death (1, 

 Bd. II, p. 331). The specific difference in these cases deserves careful 

 study. Taking the work of Pfeffer as a basis. Van HofF founded his 

 well known theory. Van Hoff also discovered the R. G. T. rule con- 

 cerning chemical reactions and Kanitz showed its applicability for 

 various cell activities (20). Recently much work has been done on 

 osmotic pressure from a quantitative standpoint, on osmotic equilibrium, 

 on permeability of organic membranes that are not protoplasmic in 

 character, on the magnitudes of osmotic pressures and electrical con- 

 ductivity and on osmotic pressure as it relates to distribution, mor- 

 phology and growth (26). 



With regard to the protoplasm numerous cjuestions of direct physi- 

 ological importance remain unsolved. For example, questions concern- 

 ing cohesion and viscosity as well as the variation in surface tension 

 need elucidation. Much interest also attaches to the various theories 

 of protoplasmic streaming and much remains to be done concerning the 

 effect of different chemical substances and other conditions (27). Tem- 

 perature combinations with certain anaesthetics require attention. The 

 locomotion of various diatoms and ciliated spores about which certain 

 points are not clear is more rapid in proportion to their size than any 



