26 THE UNITY OF NATURE. 



niinate form, then there api)ears in this 'petroplasmXas he calls it) 

 a separation of two optically different substances In this second- 

 ary plasm develop freely very small nuclei (petroblasts; and other 

 formations resembling cells (petrocellules). These two forma- 

 tions act, as he states, 'germenatively' on the ultimate develop- 

 ment of the plasma. The petroblasts are capable of turnin- into 

 crystals. The cellules and the 'blasts' take the substcince of the 

 plasma and attract them to themselves. Thus they increase. 

 Furthermore, they also multiply by division and budding. Cry- 

 stals then form by the hyalization (turning into a glassy sub- 

 stance^ of the blasts, the cellules and the cellular regions. These 

 cellular and nuclear forms attract matter to themselvesand trans- 

 form it into a substance like their own. They therefore grow. 

 They also split up ; they are thus capable of reproduction. These 

 phenomena recall those of vital processes. They represent a 

 grade much lower than life, and form a connecting link between 

 the mechanics of the inorganic world nd Biomechanics. If these 

 I^henomena are not those of life, we shall be obliged to revise the 

 ideas and notions that we have entertained of life If on the 

 contrary we regard these phenomena as vital, we shall have to 

 enlarge our definitions of life. These studies have a high value 

 in biology. Whoever has looked into the matter cannot doubt 

 that a crystalline form peculiar to eacli microbian species is pro- 

 duced in the albumenoid and plastic secretions of the micro- 

 organisms, in exactly the same manner as the phenomenon takes 

 place (.as above described) in sterile saline solutions. At any rate, 

 Schroen has proved the presence in these solutions of forms pre- 

 cedent to crystallization, which is an indisputable step forward. 

 If it is true that the precrystalline stage of solutions is a vital 

 phenomenon then Schoen's 'precellules' give us an example of 

 spontaneous generation in the present geological epoch. In the 

 beginning, all life originated from inorganic matter : the different 

 atoms formed particular associations, and their energy was dis- 

 tributed in a special way : this is an absolutely justifiable and per- 

 missible hypothesis. Very well. We have no reason whatever 

 for maintaining that this passage from the inorganic to the 

 organic world took place in only one limited geological period. 

 There is no proof that in the animnl and vegetable world, 

 these transformations are not still taking place. Methodical 



