SCIENCE 



[Vol. LV. No. 1410. 



certain algte in media from which this element 

 was absent. 



In the meantime the distilled water problem 

 had arisen to vex all physiologists and in their 

 attempt to deal with it the zoologists had 

 thrown some light on the calcium problem as 

 well. Perhaps fundamental to all was the work 

 of the English physiologist, Sydney Ringer, who, 

 as a by-product of a long series of experiments, 

 developed the generally-used normal saline solu- 

 tion known by his name. While working on the 

 characteristic effects produced by various salts 

 in prolonging the life of organisms in water 

 cultures, he noted the favorable action of cal- 

 cium salts.' He observed that in distilled 

 water calcium and other salts were extracted 

 from fish placed in it, and records that epi- 

 thelial and mucous cells seemed to become de- 

 tached from the gills. In later experiments 

 carried out on Tubifex, a freshwater worm, he 

 noted that a far more striking change took 

 place. After a time spent in water from which 

 calcium salts were excluded, the worms dis- 

 integrated. When to distilled water a calcium 

 salt was added the worms not only lived but 

 behaved very much as they did in river water.* 



His explanation of the fundamental causes 

 here operating was couched in rather general 

 language, but one gathers that he conceived 

 them to be of a physico-chemical nature, and 

 the seat of operation was thought to be in the 

 cells of the animals. There is much in Ringer's 

 work to repay the student of general physi- 

 ology. 



The fundamental features observed by him 

 were confh-med by Herbst in 1900^, when he 

 showed that in certain sea-urchin larvfe grown 

 in sea water from which Ca was lacking, the 

 epithelial tissues dissolved into their component 

 cells. When these dissociated, but still living, 

 elements were returned to calcium-containing 

 sea water, they adhered again to each other at 

 their points of contact. Herbst assumed that a 

 Verhindungsmembran exists between the cells 



■Einger, Sydney, Journ. of Physiol. 4: IV. 1883. 



sRinger, Sydney, and Sainsbury, H., Journ. of 

 Physiol., 16:4. 1894. 



9 Herbst, C, Arch. Entwicklungsmech 9: 424. 

 1900. 



when Ca is present, that this membrane is dis- 

 solved when Ca is lacking in the external me- 

 dium, thus releasing the cells of the complex. 

 When Ca is restored, this membrane is recon- 

 stituted and again cements the cells at their 

 points of contact. 



It is interesting to note in connection with 

 these observations of Herbst those of Kniid- 

 son,^'' who found that in Pfeffer's solution the 

 root cap cells of corn and Canada field peas 

 are sometimes sloughed and remain in the 

 medium isolated but living for as long a period 

 as seventy days or more. While it does not 

 appear that a Ca shortage existed in these 

 root cap cells, the possibility of such a shortage 

 v/ould be well worth investigating. 



In 1905 and 1906, while engaged in a study 

 of the physiological properties of distilled 

 water, the author, with the kindly aid of his 

 colleague, Dr. Lyman G. Briggs, applied the 

 method of electrical conductivity to the inves- 

 tigation of ion changes in solutions in which 

 seedlings were growing. It was observed that 

 the conducting capacity of distilled water in 

 vv'hich seedlings were grown increased, due, it 

 was believed, chiefly to the leaching of ions 

 from the cells of the seedlings. It was noted 

 furthermore that this leaching was checked 

 when a small quantity of a Ca salt was added 

 to the distilled water.^^ 



The use of the conductivity method was 

 extended by H. H. Bartlett and the author ^^ to 

 a study of ion changes taking place in distilled 

 water and in solutions of calcium nitrate and 

 magnesium nitrate planted with pea seedlings. 

 Owing to the fact that the method as applied 

 to this type of work had not then been care- 

 fully studied, more attention was given here 

 to the method. The conclusion was reached 

 that equilibrium concentrations of Ca and NO3 

 ions in one case and of Mg and NO3 

 ions in the other instance existed for peas 

 below which the roots would leach ions into 



10 Kniidson, L., Am. Journ. Bat., 6 : 309. 1919. 



11 True, Rodney H., Am. Journ. Bot., 1 : 255- 

 273. 1914. 



i-True, Rodney H., and Bartlett, Harley Harris, 

 Bureau of Plant Industry, V. S. Dept. of Agri. 

 Bull., 231: 1-36. 1912. 



