270 Causes and Course of Organic Evolution 



Even if we accept it, as has generally been done in the past, 

 since Pfeffer published his studies on the fertilization of fern 

 eggs, that union of the gametes results from chemotactic attrac- 

 tion between substances given off from the egg and certain 

 substances in the sperm, this seems only to be an accessory 

 and minor step in the much more fundamental union of the 

 entire gamete cells "^ith each other, and is accomplished to 

 ensure that at least one gamete shall be brought within more 

 exact attraction-range of the other. Lillie's recently pub- 

 lished studies on animal eggs not only confirm, but seem greatly 

 to extend such a view (107: 524). 



But it may well be objected here, that gamete cells amongst 

 the simpler algae are, as a rule, indistinguishable from each 

 other, and up to the point of union have been exposed to like 

 environal states. This seems to be entirely true, but we shall 

 shortly mention a possible phase of the case, to which all of 

 the preceding studies have led up, and which ^dll be further 

 discussed after study of animal sex-cells. 



It is that, in the gradual upbuilding phylogenetically of 

 the highly complex substance chromatin, such is only able, 

 under normal environal states, to grow, to divide, and to pro- 

 duce new individuals up to a definite hmit. During this period 

 of activity, the stored intra-molecular cognitic energy, that 

 has built up and energized the chromatin molecules, becomes 

 so expended and reduced in force that a stage is reached when 

 further division and growth become enfeebled or even cease, 

 unless some antithetic or complemental stores of cognitic 

 energy become accumulated in distinct groups of cells. Now 

 immediately preparatory to conjugation, in the simpler as 

 in the higher plants and animals, two noticeable changes nearly 

 always occur. First, the cell-protoplasm, under the activity 

 of biotic energy, accumulates abundant supplies of reserve 

 food in or near the future sex-cells; second, the change that has 

 already been referred to as "reduction division" occurs in 

 each sex-cell, or in some cell preliminary to its formation. 



The former act, or storing of reserve food substances, need 

 not now concern us further, except that it indicates that thus 



