R. P. Wodehouse 455 



and when allowed to cool, the precipitate formed at room tem- 

 perature and could be only slightly increased in amount by cool- 

 ing to zero. Upon examination with the microscope this pre- 

 cipitate was found to consist mostly of octahedral crystals, the 

 rest being made up of crystals of other forms but obviously of 

 the same material because similar crystal forms were found in 

 the precipitate in the control test with chemically pure potas- 

 sium oxalate. This test seems to me to be conclusive for the 

 presence of potassium. Its abundance in the sap is shown by a 

 control test done on the Bermuda sea water. Keeping everything 

 exactly the same it was impossible to get the potassium chloro- 

 platinate crystals to form even by cooling down to zero. Small 

 crystals could be caused to form only by evaporating the mixture 

 nearly to dryness and adding several volumes of absolute alcohol. 

 The conclusion arrived at from the picric acid test is thus con- 

 firmed. 



The proportions of the four kations Na, Ca, Mg, and K, could 

 not be determined quantitatively on account of the limited 

 amount of material available at the time when the work was 

 done. This is very important from the viewpoint of antagonism 

 and the author hopes to make it the subject of further investi- 

 gation. 



When the anions of sea water were tested for the presence of 

 chlorides they were indicated in all the tests made by the copious 

 precipitate produced by the sap with silver nitrate. Barium 

 chloride, however, failed to give any precipitate with the sap, 

 thus showing the absence of sulfates. Nevertheless, barium 

 chloride gave an abundant precipitate with the sea water from 

 which the plants had been taken. Occasionally a cell w r as found 

 which showed the presence of sulfate in the cell sap by the 

 barium chloride test. Upon further investigation it was found 

 that cells which were obviously dead always showed the pres- 

 ence of sulfate and that those which appeared to be in an un- 

 healthy condition frequently gave a positive test. The cells 

 which seemed to be healthy rarely gave any precipitate at all 

 with barium chloride. Accordingly the following series of tests 

 was made to determine if the presence of sulfate was associated 

 with death or injury of the cell. On holding the cells up to the 

 light the healthy ones were seen to have a uniform green color 



