THE FUNCTIONS OF LIFE. 45 



cessors, to run through the same perpetual cycle of changes 

 and renovations. 



Thus the continuance and multiplication of each species 

 may be assigned as the second of the great ends which are 

 to be accomplished in the system of living nature. A por- 

 tion of the vital power of the parent Is for this purpose em- 

 ployed to give origin and birth to the offspring. The pro- 

 cess itself, by which the germs of living beings originate, Is 

 veiled in the most Impenetrable mystery. But we are per- 

 mitted to trace many of the subsequent steps In the gradual 

 development both of vegetable and animal organizations; 

 and certainly no part of the economy of animated nature is 

 more calculated to impress us with exalted ideas of the im- 

 mensity of the scheme of Providence, and the vigilant care 

 with which the most distant consequences have been antici- 

 pated, than the history of the early periods of their existence. 

 Nothing can be more admirable than the progressive archi- 

 tecture of the frame; nothing more beautiful than the setting 

 up of temporary structures, which are required only at an 

 early stage of growth, and which are afterwards removed to 

 give place to more permanent and finished organs. 



The utmost solicitude has been shown in every part of 

 living nature to secure the perpetuity of the race, by the 

 establishment of laws, of which the operation is certain In 

 all contingent circumstances. It has also been manifestly 

 the object of various provisions to diffuse the races as widely 

 as possible over a great surface of the habitable globe. 



We are next to advert to the Important consequences 

 which, in the animal kingdom more especially, flow from 

 this law of indefinite production. As animals are ultimately 

 dependent on the vegetable kingdom for the materials of 

 their subsistence, and as the quantity of these materials is, in 

 a state of nature, necessarily limited by the extent of surface 

 over which vegetation is spread, a time must arrive when 

 the number of animals thus continually Increasing Is exactly 

 such as the amount of food produced by the earth will main- 

 tain. When this limit has been attained, no farther in- 



