or Ike fecundating Dust of the Date Tree, 55 



the acid contained in the pollen of the date tree was malic 

 acid, in order to ohtain a more rigorous demonstration of it 

 we submitted it to the following test. 



A portion of the solution of this acid, mixed with nitric 

 acid, produced a great deal of nitric gas, and furnished upon 

 cooling crystals of oxalic acid floating in a mother- water of a 

 yellowish red colour and of a bitter taste. This experi- 

 ment, as we see, confirms what the rest had announced, viz. 

 that the acid of the pollen of the date tree is undoubtedly 

 malic acid ; for no other vegetable acid is changed so easily 

 into oxalic acid by the nitric acid. It also resolves the ques- 

 tion whether this acid existed naturally in the pollen, or if 

 it be the result of a fermentation occasioned by the humidity 

 on the voyage from Egypt. We know that in fact the malic 

 acid never proceeds from a similar operation, and on the 

 coutrarv, it is itself destroyed, in order to give rise to the 

 acetic acid. 



A portion of the matter soluble in alcohol having been dis- 

 solved in a small quantity of water, we mixed carbonate of 

 soda with it ; a very brisk and frothy effervescence was pro- 

 duced; and when the saturation appeared complete, we con- 

 centrated the liquor by evaporation to the consistence of a 

 clear syrup : in this state it furnished in seven or eight days a 

 quantity of small transparent crystals : there still, however, 

 remained a great deal of matter which had not crystal- 

 lized. The crystallized salt, mixed with lime-water, precipi- 

 tated it but feebly; but some time afterwards new crystals 

 w-ere formed in the liquor. 



§ IV. Examination of the Portion of the Extract of the 

 Pollen which was insoluble in Water and in Alcohol. 



We have said that the extract of the pollen obtained by 

 the evaporation of the water with which this pollen had been 

 washed, was not entirely dissolved in the alcohol, even with 

 the assistance of heat ; and that this residue had a brown 

 colour, and a taste less acid than formerly, but nauseous. 

 This portion insoluble in the alcohol was subjected to the 

 following experiiTients, in order to ascertain its nature. 



Upon dissolving in water it precipitated a matter of a yel- 

 D 4 lowish 



