APPENDIX III. 219 



for cataract. The most careful search could not 

 find any rubidium in the lens after its removal. 



Another patient, with a double cataract, was 

 given twenty grains of chloride of rubidium. One 

 lens was extracted ten hours afterwards, and the 

 other seven days afterwards, but in neither could 

 traces of rubidium be found. 



It was found by experiment that T ^oiy ^ a 

 grain of chloride of rubidium in water was detect- 

 able by the spectrum analysis, ao^o ^ a g ra i n i n 

 urine could be distinctly observed. 



On the Passage of Chloride of Ccesium into the 

 Textures. 



Delicacy of the reaction for Ccesium. One grain of 

 chloride of caesium in 400 cub. centims. of water 

 just gives the blue caesium lines in a quantity of 

 solution that can adhere to the loop of a platinum 

 wire which took up 0.05 of solution. The T25 1 007 

 part of a grain of chloride of caesium in water can 

 be detected. If potassium is present in the same 

 solution the test is much less delicate. 



In urine, one grain of chloride of caesium in 200 

 cub. centims. is the limit of the reaction for a 

 quantity remaining on the loop of the same wire as 

 was previously used. Hence ^i^o of a grain of 

 chloride of caesium in urine can be detected. 



A guinea-pig was given three grains of chloride 

 of caesium, and twenty hours afterwards another 

 three grains. Twenty hours after the second 

 quantity it was killed. The ash of the urine 



