VEGETABLE PHYSIOLOGY. 59 



would lose its purity, and be no longer fit for the purposes for 

 which it was created. But Providence has wisely ordered it 

 otherwise. For in the first place of this partial distribution, it is 

 so arranged that this, like every other part of the creation, shall 

 be subordinate to the rest ; and that each shall take its respective 

 share in contributing to the benefit of the whole. Thus the 

 vegetable world where each portion of it, from its construction, 

 is rendered helpless and incapable of extending itself beyond the 

 spot which first gave it existence ; the sources of propagation, by 

 a very curious mechanism in some instances, and through a 

 variety of mediums in others, are made to distribute themselves 

 in all those directions which can render their perpetuation useful 

 or necessary. Thus in some, the seed vessel is. made to burst 

 its integuments with an elastic jerk, by which its seed is thrown 

 with violence to a considerable distance. Others again are 

 covered with a spiral awn or spring, blended with a number of 

 minute hairs which serve as so many fulcra, by which they cling 

 to whatever objects come in their way ; and the seed, thus 

 attached, is kept in continual motion until it falls and germinates, 

 or dies in the ground. Thus cattle, to which it frequently fixes 

 itself, by moving from place to place, and depositing the seeds 

 over a large space of ground, are often the instruments of this 

 kind of distribution. In other instances, a dispersion takes place 

 from birds and other animals feeding upon the fruits of plants, and 

 dropping the seeds after they have devoured the pulp. Some 

 carry them away to a particular spot to make a hoard of them ; 

 and such as are not consumed, germinate and become plants. 

 Others swallow the seeds, and afterwards deposit them in the 

 soil without being injured. Our own species, we know, not only 

 distribute the seed peculiar to our native climate, but also bring 

 from the most distant regions the productions of foreign countries, 

 and naturalize them in our own. The winds, also, are another 

 very powerful agent in the distribution of those seeds which are 

 purposely constructed to be acted upon by their influence ; as the 

 lichens and other seeds which float invisibly in the air, and 

 vegetate wherever they happen to meet with a suitable soil. 

 Some are furnished with a light down, others by a membraneous 



