178 THE BOTANICAL MAGAZINE IToi. xxvn. No. 321. 



After 10 da3'S, the difference of development was very striking, 

 and then the following determination was made: (See p. 177.) 

 The results show that each salt acted as a toxic or stimu- 

 lant upon the growth of rice seedlings, according to their con- 

 centrations. Magnesium sulphate and chloride, calcium chloride 

 and sodium carbonate were injurious when the concentrations 

 were greater than about Mol., while sodium sulphate, 



chloride and bicarbonate were toxic when the concentrations 

 were greater than Mol. In every salt, when the concen- 



tration was such that the toxic action ceased, the stimulating 

 effect began and attained its highest degree in the following 

 order of concentration ; magnesium sulphate Mol., mag- 



nesium chloride -k^t Mol., calcium chloride -~ fi - Mol., 

 sodium sulphate Mol., sodium chloride Mol., sodium 



carbonate -— — — — — Mol. and sodium bicarbonate 



200 1000 200 



Mol. 



Experiment II. 



On June 13th (1912), 25 rice seeds of almost uniform size 

 and specific gravity (1.158-1.185) were sown in the beakers, 

 about 5.5 cm. in diameter and 7 cm. deep, each containing 



30 cc ; of l-h iV -56' TScP W' 1550- 5000 normal 



solutions of each salt, while distilled water served as control. 

 These beakers were kept in room of normal temperature, and 

 evaporated water was supplemented with distilled water from 

 time to time to keep the solutions always in their initial con- 

 centrations. After 36 days, the difference of their development 

 was very strikingly observed and the following measurements 

 were made : 



