CATALYSIS OF LIFE. 93 



dissipated in air, were it not that by this provision, 

 it is combined with the earthy part of the soil, and 

 there retained for the use of the plants, which may 

 grow near it. 



139. Let plants be grown in the soil, whose ac- 

 tion has been considered. This introduces life into 

 the process, and it gives life to all around it. It is 

 not pretended to explain what the action of life is. 

 It has many relations with chemical processes. By 

 the refined chemistry of the present day, many pro- 

 ducts are formed, which have been usually, and in 

 fact, are now considered products of living action 

 only ; the peculiar product of life, urea, is formed 

 artificially ; so of other products, and out of carbon, 

 nitrogen, and water, may be formed as many, and 

 as complex products as are ever elaborated by a liv- 

 ing process ; yet, life is not a chemical process, and 

 were it attempted to explain how, out of the four 

 simple elements, carbon, hydrogen, oxygen, and ni- 

 trogen, all the variety of vegetable products are form- 

 ed, it might be said that life is a catalytic power. 

 The vital principle by its presence, impresses the 

 same power on the food we take, that the peculiar 

 principle in malt and in potato, called diastase, im- 

 presses on starch. It merely by its presence, gives 

 to the elements power to enter into new combina- 



