122 PROFESSOR LIONEL BEALE, F.E.C.F., F.R.S., ON THE 



eye, the alimentary canal formino', the air tubes or tracluoe 

 developing in many parts of the body, and its various segments^ 

 the legs, eyes and mandibles, and other structures of the 

 caterpillar. 



But how, and exactly by what means, all these orderly and 

 prearranged phenomena are caused and carried out, remains to 

 science so far, an insoluble mystery of living nature. One sees 

 the changes, and can as it were follow them, and they can be 

 accurately represented in photographs and drawings : but how- 

 ever closely we study and think about all that we have seen, we 

 cannot get much beyond the knowledge of the fact of their 

 appearing and continuing, while the germ is seen to grow from 

 day to day. 



We know there are particles of living matter associated with 

 every particle of tissue as it makes its appearence. The several 

 structures apioear, but they would not appear unless their 

 appearance had been preceded by living matter. This is a fact 

 — a truth throughout living nature, from tlie earliest moment of 

 existence to death, in the case of every organ and tissue, and I 

 think was as true at the time of the first creation of life, as it is 

 to-day. Structureless living matter is the only seat of action of 

 that factor " life " or " vitality," between which and all energy^ 

 forces and physical agencies, the difference is absolute. 



" Absolute " : — By this word used several times in this paper, 

 is meant a distinction so wide that, as far as I can ascertain, 

 there is no relation whatever between the changes which occur 

 in living and non-living — that tlie state of the matter, its 

 properties and energies while it is alive, cannot be compared 

 with the state of the same matter, either before it began to live, 

 or when it shall have ceased to live — that there is no analogy 

 between the states of life and non-life — no gradation from one 

 condition to the other, and that the coming of matter into life, 

 is as sudden as its death. The cessation of life in any given 

 particle of living matter however minute, whether derived from 

 the lowest simplest particle in living nature or from man him- 

 self, is also sudden. 



All the laivs of matter are compensated or suspended as 

 long as matter is alive, but come again into operation, the 

 instant the living matter ceases to live. This distinction 

 between life and non-life all through our world, is tlierefore 

 correctly described as absolute. 



For the excellent photographs I have the pleasure of showing 

 you, of the eggs of Botys hyalinalis from the day on which they 

 were laid to the day of emergence of the fully formed caterpillar. 



