SPROUTING OF SEEDS. 91 



"When polished plates of marble, dolomite, or osteolite 

 (calcium phosphate), are covered with sand, to a depth of a 

 few inches, and seeds are then sown in the sand, the roots, 

 which strike downward, soon meet the polished surface of 

 the mineral, and grow upon and in close contact with it. 

 After a few days an impression of the root system is found 

 corroded in rough lines into the smooth surface ; every root 

 has dissolved, at the points of contact, a small portion of the 

 mineral, by means of the acid water which permeates its outer 

 cell walls.' 7 



Here we have, clearly set forth, and proven by experiment, 

 a virtual gastric juice, a substance elaborated and sent out to 

 meet food material, dissolve it, and render it fit to be brought 

 in, by osmosis, the same as in the higher animals and in the 

 lower forms of unicellular life. 



It is not yet shown, in this case, that this is a specialized 

 soluble ferment substance, but it evidently acts the part of 

 such a substance, and, while this is so clearly shown, its com- 

 position makes but little difference, so far as our present pur- 

 pose is concerned, which is to show that all forms of life are 

 dependent upon digestion in some form, for the preparation 

 of the material upon which they subsist for absorption. 



It is not claimed that all material used by the life force 

 must undergo this kind of change. Water is used without 

 such change by all forms of life, and probably many other 

 substances are so used. 



SPROUTING OF SEEDS. 



With every egg that is formed there is a provision for the 

 nourishment of the embryo until the animal has developed 

 the organs by which it is to prepare its food for assimilation. 

 The egg is composed of two parts, an embryo, and formed 

 material for the nutrition of that embryo. In the seed there 

 5* 



