78 Prof. J. Keynolds Green and Mr. H. Jackson. [Mar. 22, 



gave the same weight as the original juice, 02 gramme. The treatment 

 with the juice had increased the original reducing power 50 per cent., 

 showing the presence of invertase. 



Further experiments upon the same point showed that invertase appears 

 in the endosperms at a very early period of germination, usually after a few 

 hours ; it is well established in 48 hours, and increases in amount up to the 

 stage at which a good root system has been established. In a series of 

 experiments upon its development during the germination three stages were 

 compared : (1) The seeds had the radicle protruding about 0-3 inch; (2) The 

 roots were 1 inch long and the secondary rootlets were just cracking the 

 primary root ; (3) There was a good root system and the endosperms were 

 about half consumed. Extracts were made of all these and 2 c.c. of each 

 allowed to act on 20 c.c. of a 1 per cent, solution of cane-sugar, at 40° C. for 

 24 hours. They were then titrated with Fehling's fluid, when the weights 

 of cupric oxide obtained were : — 



(1) 0-003 gramme ; (2) 0-006 gramme ; (3) 0-007 gramme. 



These experiments lead us to the conclusion that the sugars of the 

 endosperms may be put down as cane-sugar and invert sugar. 



The relative quantities of these two sugars during the progress of germina- 

 tion have been ascertained and are given in Table B. Experiments on this 

 point have been published by Du Sablon in the paper already referred to. 

 He states that he found non-reducing sugar to be slightly in excess of 

 reducing sugar in the resting seed and to increase more rapidly than the 

 latter till the radicle is about 1*5 to 2 inches long, when the reducing sugar 

 becomes equal in amount and, later on, preponderates considerably. 



Our experiments were carried out in the following manner : — A number 

 of seeds were germinated in sawdust in an incubator kept at a temperature 

 of 22° C. In each experiment three were taken, peeled, and ground up to 

 a smooth paste in an agate mortar. The paste was then boiled with 

 a sufficient quantity of water for an hour, the extract strained off, filtered, 

 and divided into two. Half was warmed to 40° C. with 1 c.c. of a solution 

 of invertase prepared from yeast, and kept at that temperature for 24 hours. 

 The invertase solution was ascertained to be free from sugar or other 

 substance capable of reducing Fehling's fluid. The two halves of the 

 extract were then titrated side by side, and the weight of the cupric oxide 

 taken in each case. From these weights the quantities of the two sugars 

 were computed in the usual way. 



