BIOLOGY 



CHAPTER I 



THE ORIGIN OF LIFE 



IT is an indisputable fact that all the living organisms 

 of which we have any cognisance at the present time 

 arise from pre-existing organisms. As to the origin of 

 life upon earth we know nothing. Various opinions 

 have been expressed from the times of the early philo- 

 sophers up to the present day. Leaving all the earlier 

 beliefs as to the origin of life out of the question, we come 

 to that which seems to be held by a very large number 

 of scientific workers at the present time, namely, that 

 living matter has been evolved from non-living matter 

 on the earth's surface. 



According to this view of the origin of life, all the 

 criteria generally used in differentiating the living from 

 the non-living are useless in so far as they are equally 

 applicable to both. Movements which were thought to 

 be characteristic of the lower organisms are found to be 

 precisely reproduced by such substances as oil-drops and 

 mercury globules. Even the taking in of food and its 

 elaboration, the process of growth and such periodic 

 functions as reproduction can no longer be considered a 



characteristic feature of living matter ; for all these are 



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