1905.] On the Germination of Seeds of the Castor Oil Plant. 81 



be obtained after a seed has been exposed to warmth and moisture for 

 24 hours, and it becomes more and more intense for six or seven days. 



While the reaction to litmus paper becomes very prominent, only very 

 small quantities of acid can be obtained from the seed. The expressed juice 

 of a parcel of germinating seeds was titrated with decinormal potash 

 solution, and 10 c.c. of it neutralised only 4 c.c. of the alkaline solution. 

 We made several attempts to prepare it in quantity by experimenting upon 

 about a thousand seeds at once. They were germinated for a week, and 

 the endosperms separated from the embryos, ground and boiled in water 

 in a steriliser for several hours. After straining and filtering part of the 

 extract was distilled by the aid of steam. The distillate was practically 

 neutral in reaction, the merest trace of acidity coming over. The acid in 

 the remainder, after removal of uncoagulable proteid, was precipitated by 

 normal lead acetate, and the lead salt filtered off, suspended in water and 

 treated with a stream of sulphuretted hydrogen till the lead was all con- 

 verted into sulphide. The filtrate from the latter was concentrated to a 

 small bulk, and the precipitation and subsequent treatment repeated. The 

 final filtrate was concentrated to a small bulk in vacuo over sulphuric acid. 



The acid residue, somewhat syrupy in consistence, was then washed 

 repeatedly with dry ether, which dissolved a certain quantity, leaving 

 behind, however, a good deal of acid which was soluble in water only. 

 The bulk of the latter was ascertained to be phosphoric acid. The solution 

 in ether was concentrated in vacico and formed a syrupy residue. We found 

 it impossible to crystallise this acid or to obtain a crystallisable salt. Many 

 attempts were made to effect crystallisation, but in only one case was any 

 success obtained, and then only a few crystals on the surface of the syrup 

 were formed. Unfortunately, therefore, the nature of the acid has not been 

 ascertained. 



After looking for the source of this organic acid we again find reason to 

 attribute it to the oil. We have already pointed out (p. 75) that the amount 

 of lecithin formed is not sufficient to account for the disappearance of the 

 whole of the oil of the seed, but that another fate awaits a considerable 

 quantity. It was suggested in the former paper* that the acid of the 

 germinating seed was derived from the oil by certain processes of oxidation, 

 and served as the means of its utilisation. It is extremely unlikely that this 

 acid is directly or indirectly connected with the sugars. We think we have 

 here the explanation of the gradual diminution of the oil in the early stages 

 of germination, and of the development of the coincident acidity. The acid 

 reaction of the endosperm sets in before any change can be detected in the 



* Green, loc. cit., p. 385. 

 VOL. LXXVII. — B. G 



