15 



the aiiimars highest feat of constructive chemistry behig to con- 

 vert dead protoplasm mto that living matter of life which is 

 appropriate to itself. Therefore, in seeking for the origin of 

 protoplasm, we must eventually turn to the vegetable world. 

 The fluid containing carbonic acid, water, and ammonia, which 

 oiFers such a barmecide feast to the animal, is a table richly 

 spread to multitudes of plants ; and with a due supply of only 

 such materials, many a plant will not only maintain itself in 

 vigor, but grow and multiply until it has increased a million-fold, 

 or a million million-fold, the quantity of protoplasm which it orig- 

 inally possessed ; in this way building up the matter of life, to 

 an indefinite extent, from the common matter of the universe. 

 Thus the animal can only raise the complex substance of dead 

 protoplasm to the higher power, as one may say, of living proto- 

 plasm ; w^hile the plant can raise the less complex substances — car- 

 bonic acid, water, and ammonia — to thesame stage of living pro- 

 toplasm, if not to the same level. But the plant also has its lim- 

 itations. Some of the fungi, for example, appear to need higher 

 compounds to start with ; and no known j^lant can live upon the 

 uncomj)ounded elements of protoplasm, A plant supplied with 

 pure carbon, hydrogen, oxygen, and nitrogen, phosphorus, sul- 

 phur, and the like, would as infallibly die as the animal in his 

 bath of smelling-salts, though it would be surrounded by all the 

 constituents of protoplasm. Nor, indeed, need the process of 

 simplification of vegetable food be carried so lar as this, in order 

 to arrive at the limit of the plant's thaumaturgy. 



Let w^ater, carbonic acid, and all the other needful consti- 

 tuents, be supplied without ammonia, and an ordinary j)lant will 

 still be unable to manufacture protoplasm. } Thus the matter of 

 life, so far as we know it (and we have no right to speculate on 

 any other) breaks up, in consequence of that continual death 

 which is the condition of its manifesting vitality, into carbonic 

 acid, water, and ammonia, which certainly possess no j)roperties 

 but those of ordinary matter. And out of these same forms of 

 ordhiary matter, and from none which are simpler, the vegetable 

 world builds up all the protoplasm which keeps the animal world 

 agoing. Plants are the accumulators of the power which animals 

 distribute and disperse, f ^ ■*^fc^ 



But it wuU be observed, that the exist^|||f the matter of 

 life de pends on the pre-existence of certain compoiui ds. namely, 

 cal'bonic acid, water, and ammonia. Withdraw any one of these 



