ADDRESS. lx.W 



only be vaguely surmised, and in regard to which no exact information can 

 be obtained. Or, secondly, evading the difficulty of strict cosmical evolution, 

 we might suppose that vital conditions may have been coeval with the first 

 existence of physical and chemical properties in the rest of natural bodies. 

 But this hypothesis would be exposed to the objection that, according to the 

 cosmical view generally held by physicists, the whole materials composing 

 the earth have originally been subjected to incandescent heat. Nor is the 

 difficulty abolished, but only removed to a more remote period, by the suppo- 

 sition of the transport of germs from another planet or their introduction 

 by means of meteorites or meteoric dust ; for, besides the objection arising 

 from the circumstance that these bodies must have been subjected to a very 

 high temperature, we should still have every thing to learn as to the manner 

 in which the germs originated in the far distant regions of space from which 

 they have been conveyed. 



The incompleteness of the geological record leaves us in the dark as to the 

 time at which the first dawnings of life appeared in the lower strata of the 

 earth's surface. The most recent researches tend to carry the origin of life 

 back to a much earlier period than was at one time believed, and (if the 

 famous Eozoon be admitted as evidence) even into that of the Laurentian 

 strata. But if doubts should still prevail with regard to the presence of 

 definite organized forms in the older sedimentary strata, the occurrence in 

 them of carbon in the form of graphite in large quantities makes the previous 

 existence of living organisms at least possible, and it may bo that the com- 

 plete metamorphosis which these rocks have undergone has entirely removed 

 all definite traces of organization. 



Nor have we the means from geological data of determining whether the 

 beings of the vegetable or of the animal kingdom first made their appearance. 

 If we adopt the view which has for some time been entertained by physio- 

 logists that animals are entirely dependent, directly or indirectly, on plants 

 for the material which constitutes their living substance, and that plants, as 

 constructive agents, alone have the power to bring together the elements of 

 lifeless matter, from such states as carbonic acid, water, and ammonia, into 

 the condition of the living solid, the inference would be inevitable, at least 

 for the great majority of the animal creation, that they must have been 

 preceded by plants. But palaeontology is as yet silent on this interesting 

 question ; and, if we consider the remarkable approach which is made in 

 structure and properties between the lowest and simplest members of the two 

 kingdoms of organic nature, so that at last all distinction between them 

 seems entirely to vanish, and a set of organisms is found partaking equally 

 of animal and vegetable characters, or, rather, exhibiting properties which 

 are common to them both, wo shall hesitate to postulate confidently for the 

 primitive antecedence of vegetable life, although, perhaps, in later epochs the 

 preexistence of vegetables may be looked upon as necessary to the life of 

 more developed animal organisms. 



