THE SILKWORM ITS FORM AND LIFE HISTORY. 15 



however, is only one stage in its career, and we have now to sketch 

 its complete life history. Suppose we take an individual specimen ; 

 it commences its independent life, as most animals do, in the form 

 of an egg. This egg is a minute object, about the size of a turnip- 

 seed, nearly round, but flattened. When first laid it is of a 

 bright yellow colour, and at that time no trace of such a thing as 

 a "worm" could possibly, by the most diligent scrutiny, be found 

 inside. It seems simply to consist of a little semifluid matter 

 surrounded by a horny skin. 



But there are wonderful powers lying dormant in this tiny speck 

 of matter, and within the limits of that small cell there are destined 

 to go on changes more marvellous, if possible, than any that take 

 place during all the rest of its life. Under the influence of a 

 suitable temperature, there is to be formed out of that little speck 

 of living matter, a tiny grub, or caterpillar, which, on reaching its 

 completion, is to eat its way out of its little prison house, and take 

 its place in the world as an item in the mighty crowd of living 

 creatures that daily fulfil their destiny upon its surface. Could 

 we but peep inside that tiny eggshell, and, gazing down the tube 

 of a powerful microscope, watch the changes as they take place, 

 we should be inclined, adapting language applied by Professor 

 Huxley to the development of a different animal, to confess that 

 " the plastic matter undergoes changes so rapid and yet so steady 

 and purpose-like 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, a portion of the mass 

 is divided and subdivided into smaller and smaller portions, . . . 

 and then it is as if a delicate finger traced out" gradually the contour 

 of the body, "fashioning flank and limb into due 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." 



But the outward signs of these wonderful changes are few and 

 insignificant ; they consist almost entirely in changes of colour. A 

 few days after having been laid, the egg begins to deepen in 

 colour, becoming first brown, then reddish grey, and lastly slaty 

 grey, or greenish, according to the breed. It also becomes 

 depressed in the centre. In this condition it remains all the 

 winter, the gradually falling temperature retarding its further 

 development. 



When, however, the temperature rises again towards the close 

 of spring, a new series of changes in the reverse order sets in, and 



