488 Mr. W. Stiles and Dr. F. Kidd. The Comparative 



Metlwd. 



The method used is that described in a former paper (12). The experi- 

 ments were carried out in triplicate. All the results compared with one 

 another were obtained with the same sample of tissue and from experiments 

 carried on contemporaneously. 



The concentration selected throughout was N/50, as with this concentra- 

 tion of salts of " nutrient " or harmless metals exosmosis is likely to be small 

 in comparison with the absorption, so that the results will give a* near 

 approximation to the relative rates of absorption from the various solutions. 

 When exosmosis takes place to any great extent the tissue loses water and 

 its turgidity. Carrot in solutions of nutrient or harmless metals of a con- 

 centration of N/50 remained turgid right up to the conclusion ot the 

 experiments. 



In each series the salts employed had a common anion or kation, so that 

 the influence of different ions on the rate of absorption is displayed. Four 

 series with carrot and three with potato were carried out, the common ions 

 in the carrot series being respectively chloride, sulphate, nitrate, and potas- 

 sium. Chloride, sulphate, and nitrate series were carried out with potato. 



Experimental Results. 



1. Chlorides. — The chlorides used were those of potassium, sodium, lithium, 

 and calcium. The changes in conductivity in the case of carrot are given in 

 the accompanying Table, and are shown graphically in fig. 1. 



Table I. — Carrot in Solutions of various Chlorides of Concentration N/50. 



Potassium chloride. 



Sodium chloride. 



Lithium chloride. 



Calcium chloride. 



Time 



Change in 



Time 



Change in 



Time 



Change in 



Time 



Change in 



in 



electrical 



in 



electrical 



in 



electrical 



in 



electrical 



hours. 



conductiTity. 



hours. 



conductiritj. 



hours. 



conductivity. 



hours. 



conductivity. 















0-25 



-101 



0-5 



- 145 







0-5 



- 64 



•-5 



-113 



1-0 



- 175 



1 -0 



- 80 



1-0 



- 67 



1 -0 



-113 







2-0 



- 117 











6-38 



- 835 



6-62 



- 222 



6-12 



-119 



6-20 



-143 



18 -28 



- 758 



18 -62 



- 560 



18 -0 



-257 



18-0 



-176 



28-75 



-1138 



29 -0 



- 896 



28 -5 



-374 



28 -5 



-230 



43 -25 



-1497 



43-5 



-1228 



43 -0 



-449 



43 -0 



-341 



49 -25 



-1595 



49-5 



-1329 



49-0 



-489 



49 -0 



-371 



91 -25 



-2039 



91 -5 



-1677 



91 -0 



-599 



91 -0 



-628 



