The Outlook 479 



size, hair form, etc., which behave as units in inheritance? 

 Is sex purely an inherited character, subject to Mendelian 

 laws, or is it determined by conditions of metabolism or other- 

 wise, and if so is it subject to experimental control? And 

 what is the significance of the curious sex intergrades which 

 have recently been described, and which are ''neither fish, 

 flesh, nor good red herring"? How and why did sex arise? 

 There are some animals, such as Hydra, which reproduce both 

 sexually and asexually. What are the factors inducing sexual 

 reproduction in such forms ? And what is its function ? Does 

 it exercise a rejuvenating influence upon the race, or does it 

 serve to produce variation and thereby lead to evolution and 

 adaptation? Or do both of these, or yet other explanations 

 contain the truth? 



Why do some animals reproduce by parthenogenesis at one 

 period in their life history and sexually at another? And 

 what is the significance of parthenogenesis, which in some 

 cases has gone so far that males are extremely rare, and may 

 possibly in some species have disappeared entirely ? At any 

 rate if they occur, they are yet to be discovered. 



Surrounded as we are by speculation and uncertainty in 

 the realm of evolution and inheritance, we enter a veritable 

 terra incognita when we come to speculate upon the essence 

 of life itself. Is life purely a physico-chemical process, and 

 the organism a mere machine controlled by forces extraneous 

 to itself ? And if so, what are the physico-chemical reactions 

 which constitute life? Or is life a process outside the realm 

 of physics and chemistry ? Are our concepts of consciousness 

 and intelligence, of volition and of soul, realities, or mere 

 figments of the imagination? Or is there yet some middle 

 course which we may steer between the Scylla of "mechanism" 

 on the one hand and the Charybdis of "vitalism" on the 

 other ? 



If life be an unsolved problem, equally so is the cessation 

 of life or death. Is death inherent in life or was life pri- 

 marily unending, and death secondarily derived from factors 

 outside of life itself? And what of the origin of life? Is 

 Harvey's dictum "Omne vivum ex vivo" necessarily true? 

 Or may lifeless matter to-day be generating life and continue 

 to do so throughout the ages, as it did at some time in the 

 past? 



If we are some day to solve the riddle of life, we shall then 

 be able to create life. While some enthusiasts have from time 

 to time claimed that they have done this, their claims are yet 

 unsubstantiated, but the possibility of such an achievement 

 looks less remote to us today, than would have seemed the 

 Rontgen ray or the wireless telegraph to our forefathers. 



