30 READINGS IN BIOLOGICAL SCIENCE 



pound solutions which grow into systems of Theology or of Philosophy, 

 or veiled in musical language which suggests more than it asserts, take the 

 shape of the Poetry of an epoch. 



Each such answer to the great question, invariably asserted by the fol- 

 lowers of its propounder, if not by himself, to be complete and final, re- 

 mains in high authority and esteem, it may be for one century, or it may 

 be for twenty: but, as invariably. Time proves each reply to have been a 

 mere approximation to the truth — tolerable chiefly on account of the igno- 

 rance of those by whom it was accepted, and wholly intolerable when tested 

 by the larger knowledge of their successors. 



In a well-worn metaphor, a parallel is drawn between the life of man 

 and the metamorphosis of the caterpillar into the butterfly; but the com- 

 parison may be more just as well as more novel, if for its former term we 

 take the mental progress of the race. History shows that the human mind, 

 fed by constant accessions of knowledge, periodically grows too large for 

 its theoretical coverings, and bursts them asunder to appear in new habili- 

 ments, as the feeding and growing grub, at intervals, casts its too narrow 

 skin and assumes another, itself by temporary. Truly the imago state of 

 Man seems to be terribly distant, but every moult is a step gained, and of 

 such there have been many. 



Since the revival of learning, whereby the Western races of Europe 

 were enabled to enter upon that progress towards true knowledge, which 

 was commenced by the philosophers of Greece, but was almost arrested 

 in subsequent long ages of intellectual stagnation, or, at most, gyration, 

 the human larva has been feeding vigorously and moulting in proportion. 

 A skin of some dimension was cast in the i6th century, and another towards 

 the end of the i8th, while, within the last fifty years, the extraordinary 

 growth of every department of physical science has spread among us 

 mental food of so nutritious and stimulating a character that a new ecdysis 

 seems imminent. But this is a process not unusually accompanied by many 

 throes and some sickness and debility, or, it may be, by graver disturbances; 

 so that every good citizen must feel bound to facilitate the process, and 

 even if he have nothing but a scalpel to work withal, to ease the cracking 

 integument to the best of his ability. 



The importance of such an inquiry is indeed intuitively manifest. 

 Brought face to face with these blurred copies of himself, the least thouqht- 

 ful of men is conscious of a certain shock, due, perhaps, not so much to 

 disgust at the aspect of what looks like an insulting caricature, as to the 

 awakening of a sudden and profound mistrust of time-honoured theories 

 and strongly-rooted prejudices regarding his own position in nature, and 

 his relations to the under-world of life; while that which remains a dim 

 suspicion for the unthinking, becomes a vast argument fraught with the 

 deepest consequences, for all who are acquainted with the recent progress 

 of the anatomical and physiological sciences. 



