Messrs. Brown and Escombe. On the Depletion of the 



As these conclusions are in many respects opposed to those arrived 

 at by one of us a .few years ago, we have considered it necessary to 

 institute a further series of experiments, and to re-examine the 

 whole question of the mutual dependence of the embryo and endo- 

 sperm. In doing this we have endeavoured to free our minds of any 

 bias which might, even unconsciously, have been given by our 

 previous experiments, and to subject those experiments to the 

 strictest possible criticism. 



Broadly speaking, the question resolves itself into a consideration 

 of the various causes at work in bringing about the solution of the 

 reserve material of the seed in preparation for its absorption by the 

 scutellum of the young plant, and the due apportionment of this 

 work to (1) the embryo itself, (2) the amyliferous cells, and to (3) 

 the peripheral cells of the endosperm, the so-called " aleurone-layer " 

 or " Kleberschicht." 



In addition to this, we have to take into account the possibility of 

 eome of the changes being brought about by enzymes pre-existent in 

 the amyliferous cells, which may be altogether independent of the 

 present life of the cytoplasm. We have, further, to determine the 

 part played by micro-organisms accidentally brought into action 

 during the experiments, and to eliminate the changes due to their 

 influence alone. 



In work of this character we can only attain to results of any 

 value by a great multiplication of experiments made in such a 

 manner as to admit of the close and frequent comparison of different 

 series performed under every conceivable variation of conditions. 



All our new work was conducted on barley only, and the results 

 are based on very many hundreds of experiments, extending over a 

 period of more than twelve months, during which time various 

 possible sources of error were gradually excluded. 



As long as we confine our attention to intact seeds the disturbing 

 influence of micro-organisms is but small, but the case is different 

 when the seed envelopes have to be cut through and the embryo 

 removed, the endosperm, thus bared and deprived of its protective 

 coatings, being then open to the attack of bacteria and moulds, 

 which thrive in the culture-medium employed, and by their action 

 induce changes in the contents and cell-membranes of the endosperm- 

 cells which it is almost impossible to distinguish from those initiated 

 by the cells themselves, supposing them to be living and active 

 units. 



At the outset of the investigation we spent a considerable time in 

 endeavouring to find some antiseptic agent possessed of such a differ- 

 ential action as to inhibit, or at any rate to materially retard, the 

 growth of micro-organisms, whilst not interfering with the normal 

 growth of vegetable organs. Many various reagents were tried, 



