THE WEIGHT OF THE EMBRYO 405 



disposition of the food-reserve ; and one has only to refer 

 to Lord Avebury's volume on seedlings in the International 

 Scientific Series to become apprised of this fact. For example, 

 we have its disposition in the cotyledons, as in many leguminous 

 seeds ; its disposition in the hypocotyl, as in the Barringtonia 

 and with some Guttiferae, and its disposition outside the 

 embryo altogether, as occurs with many plants. The embryo 

 in different resting seeds varies so much in its stage of develop- 

 ment and so much in its relation to the reserve supply of food 

 that one hesitates to consider the matter of its relative weight 

 at all. 



However, one has only to observe that whilst over 1 00,000 

 Juncus embryos are required to make up the weight of a single 

 embryo of the Coco-nut palm, they are in relation to the 

 kernel more than 200 times as heavy, in order to perceive that 

 a study of the secondary relations involved in such measure- 

 ments may lead to some interesting conclusions. Whilst the 

 Coco-nut embryo is in an absolute sense one of the very largest 

 and heaviest amongst embryos of its kind, it is in a rektive 

 sense, as compared with the kernel, one of the very smallest 

 and lightest. The subject from this standpoint seems to lend 

 itself for inquiry, and here again the principal instrument of 

 investigation is the balance, weight as a general rule connoting 

 size. 



The estimation of the weight of the embryo in very small Method of 

 seeds, as in those of the Common Rush (Juncus), is easier than thl^^ght 

 it might at first seem to be. It soon became apparent to me ™*2^^*^^ 

 that I could begin by ascertaining the proportional bulk and 

 the proportional weight of the embryo as part of the kernel in 

 a seed that could be easily examined, and that by a comparison 

 of the two results a constant error might be found which 

 could be applied in those numerous cases where, owing to 

 the use of the balance being impracticable, one is compelled 

 to rely on the proportional size of the embryo for the clue 

 to its weight. 



As suiting my purpose the light brown seeds of dehiscing 



