410 TENDENCIES OF NATURE TO PRODUCE. 



out her still small whisperings for the ears of those 

 that can hear them. 



The extraordinary tendency that Nature has to 

 produce, and the vigilant perseverance she main- 

 tains to occupy all substances as a soil for her pro- 

 ductions, when they arrive at a state fitting for her 

 purposes, is a well-known fact, and is perfectly in 

 consistency with the uniform habit she preserves, 

 of letting i( no fragment be lost." All things tend 

 upwards, from some original, through an infinity of 

 gradations, though the beginning and termination 

 may not always be perceived, nor the links of this 

 vast chain be found. The most obscure plants, 

 agarics or mucor, as far as we know, perfect their 

 seed, and give birth to other generations; but there 

 is a fine green substance, observable upon the sprays 

 of trees, stems of various shrubs in every hedge, 

 upon old rails and exposed wood-work, leaving a 

 powdery mark upon one's coat that has rubbed 

 against such places, which I have always considered 

 as the very lowest rudiment of vegetation. This 

 matter, submitted to examination in the microscope, 

 presents no foliage or plant-like form, but appears 

 a kind of pollen, a capsule, or a perfected seed, sus- 

 pended on a fine fibre ; but from the extreme small- 

 ness of it I speak with hesitation, not being able 

 to define it satisfactorily with the most powerful 

 lens. If it be, as I have conjectured, a perfected 



