220 Pennington — A Chemico-Pliysiological 



phosphorus, as calcium phosphate, and alkalies, in the 

 form of sulphates, carbonates, and chlorides. It was taken 

 up with water and thoroughly boiled out, the phosphorus 

 being estimated in the insoluble portion by separating with 

 ammonium molybdate, and weighing as magnesium pyro- 

 phosphate. 



Loew * states that mono-potassium phosphate is soluble 

 in absolute ether to the extent of 3 mg. in 100 cc. This 

 solubility introduces an error into the estimation of 

 lecithin as determined by the phosphorus content of the 

 ether-alcohol extract, provided this phosphate occurs in 

 the plant. Another, and more general opportunity for 

 error lies in the fact that in the estimation of lecithin 

 the material is preferably dried at very low temperatures. 

 Much water is in this way retained in the tissues, 

 and so carries out the soluble salts during the extrac- 

 tion. Both sodium and potassium were found in the 

 extract in quantities far beyond those required to combine 

 with the phosphoric acid. A trace of magnesium was also 

 detected. This was probably from magnesium sulphate, 

 which is somewhat soluble in absolute alcohol. Sulphuric 

 acid was present, perhaps arising from the oxidation of 

 organic sulphur, perhaps in combination with the alkali as 

 sulphate. 



Lecithin contains 4 per cent, of phosphorus and 7.56 per 

 cent, of trimethylamine. Calculating the lecithin from 

 the phosphorus found, we have 0.19 per cent, contained in 

 the plant. If we make the calculation upon the basis of 

 trimethylamine, we have 5.97 per cent, or a quantity over 

 thirty times as great as that indicated by the phosphorus 

 content. 



Many attempts were made to isolate crystals of lecithin 

 from the plant, but all were fruitless. 



Though these experiments do not absolutely prove that 

 lecithin is entirely absent from the plant, they do indi- 

 cate that the evolution of trimethylamine is from another 



* Pfliiger's Arch., Vol. 79- 



