XIL] THE ORIGIN OF SPECIES. 227 



less, the more conversant he becomes with her operations ; but 

 of all the perennial miracles she offers to his inspection, perhaps 

 the most worthy of admiration is the development of a plant or 

 of an animal from its embryo. Examine the recently laid egg of 

 some common animal, such as a salamander or a newt. It is 

 a minute spheroid in which the best microscope will reveal 

 nothing but a structureless sac, enclosing a glairy fluid, holding 

 granules in suspension. But strange possibilities lie dormant in 

 that semi-fluid globule. Let a moderate supply of warmth reach 

 its watery cradle, and the plastic matter undergoes changes so 

 rapid and yet so steady and purposelike in their succession, that 

 one can only compare them to those operated by a skilled 

 modeller upon a formless lump of clay. As with an invisible 

 trowel, the mass is divided and subdivided into smaller and 

 smaller portions, until it is reduced to an aggregation of granules 

 not too large to build withal the finest fabrics of the nascent 

 organism. And, then, it is as if a delicate finger traced out the 

 line to be occupied by the spinal column, and moulded the 

 contour of the body ; pinching up the head at one end, the tail 

 at the other, and fashioning flank and limb into due salamandrine 

 proportions, in so artistic a way, that, after watching the process 

 hour by hour, one is almost involuntarily possessed by the notion, 

 that some more subtle aid to vision than an achromatic, would 

 show the hidden artist, with his plan before him, striving with 

 skilful manipulation to perfect his work. 



As life advances, and the young amphibian ranges the waters, 

 the terror of his insect contemporaries, not only are the nutritious 

 particles supplied by its prey, by the addition of which to its 

 frame growth takes place, laid down, each in its proper spot, and 

 in such due proportion to the rest, as to reproduce the form, the 

 colour, and the size, characteristic of the parental stock; but 

 even the wonderful powers of reproducing lost parts possessed 

 by these animals are controlled by the same governing tendency. 

 Cut off the legs, the tail, the jaws, separately or all together, 

 and, as Spallanzani showed long ago, these parts not only grow 

 again, but the redintegrated limb is formed on the same type as 



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