I EMBRYOLOGICAL ARGUMENTS 29 



the facts of embryology. Embryology is merely an 

 evolution, and to study the development of any given 

 organism is to study its evolution from a single ele- 

 mentary cell the egg-cell to the stage when this 

 has become capable of leading an independent or 

 semi-independent life, and has acquired a form and 

 complexity of structure which are truly marvellous. 

 In many cases this evolution lasts some weeks, some 

 months at the longest, and the organism thus evolved 

 merely needs to acquire larger dimensions by growth ; 

 but in many cases also there are breaks in the evo- 

 lution process, and when one point is attained the 

 process stops for some time, and is resumed later on. 

 Such is the case in most butterflies where the evolution 

 or development takes place in two or three periods, 

 the adult period being singularly short, and some- 

 times hardly exceeding a few hours, during which 

 reproduction is the only function accomplished, and, 

 in fact, the butterfly stage of life has no other object 

 than reproduction. 



This process of evolution is a most marvellous one. 

 While the brain the minute speck of brain of an 

 ant may well cause the naturalist and thinker to 

 wonder, by reason of the varied and complex acts it 

 originates, the mere cell out of which a most complex 

 organism with innumerable functions develops in the 

 course of a few years, yielding a brain such as that 



