SOURCE OF LIFE. 283 



themselves new qualities qualities which were 

 not merely previously unknown; but which 

 actually did not exist. Now if that be true of 

 any one kind of matter, be that what it may, there 

 is no denying it to any and every kind of matter ; 

 and if that were the case, we should have all the 

 species of matter confounded and jumbled together; 

 and that is a conclusion against which we should 

 most especially be on our guard, because it would 

 unhinge all our natural knowledge. 



When we come to examine plants and animals, 

 and reflect upon the immense variety which they 

 present, in size, in structure, and in habits, we can- 

 not easily avoid putting the question, " Why they 

 should be thus or thus." But though a tempting 

 question it is a dangerous one, and we must pre- 

 sume no more than we see. From what was for- 

 merly said of the germs of the oak, we may form 

 some notion of how impossible it is to trace back- 

 wards through annual successions, and often 

 through successions of several races in the year, 

 plants which, in their full grown state, are merely 

 or not at all visible to the eye, and animals which 

 are equally and even more minute. 



Yet why should we trouble ourselves about those 

 minute points ? There is enough to be seen in 

 such a manner as we can understand it, in both 

 kingdoms of living and organized nature. And 

 as the members of those kingdoms are more sus- 

 ceptible than matter deprived of life, we have 

 them more varied both by place and time. 



There is not a more beautiful study than the 

 climatal variation of the vegetable tribes, in their 

 gradation from the extreme north, where they are 

 few, to the luxuriance of the tropical forests and 



