504 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1912. 



THE EVOLUTIONARY HYPOTHESIS AS APPLIED TO THE ORIGIN OF LIFE. 



I assume that the majority of my audience have at least a general 

 idea of the scope of this hypothesis, the general acceptance of which 

 has within the last 60 years altered the whole aspect not only of 

 biology, but of every other branch of natural science, including 

 astronomy, geology, physics, and chemistry.* To those who have 

 not this knowledge I would recommend the perusal of a little book 

 by Prof. Judd, entitled "The Coming of Evolution," which has 

 recently appeared as one of the Cambridge manuals, I know of no 

 similar book in which the subject is as clearly and succinctly treated. 

 Although the author nowhere expresses the opinion that the actual 

 origin of life on the earth has arisen by evolution from nonliving 

 matter, it is impossible to read either this or any similar exposition in 

 which the essential unity of the evolutionary process is insisted upon 

 without concluding that the origin of life must have been due to 

 the same process, this process being, without exception, continuous, 

 and admitting of no gap at any part of its course. Looking there- 

 fore at the evolution of living matter by the light which is shed 

 upon it from the study of the evolution of matter in general, we 

 are led to regard it as having been produced, not by a sudden alter- 

 ation, whether exerted by natural or supernatural agency, but by 

 a gradual process of change from material which was lifeless, through 

 material on the borderland between inanimate and animate, to ma- 

 terial which has all the characteristics to which we attach the term 

 "life." So far from expecting a sudden leap from an inorganic, or 

 at least an unorganized, into an organic and organized condition, 

 from an entirely inanimate substance to a completely animate state 

 of being, should we not rather expect a gradual procession of changes 

 from inorganic to organic matter, through stages of gradually in- 

 creasing complexity until material which can be termed living is 

 attained ? And in place ol looking for the production ot fully formed 

 living organisms in heremeticaUy sealed flasks, should we not rather 

 search Nature herself, under natural conditions, tor evidence of the 

 existence, either in the past or in the present, of transitional forms 

 between living and -nonliving matter? 



The difficulty, nay the impossibility, of obtaining evidence of 

 such evolution from the past history of the globe is obvious. Both 

 the hypothetical transitional material and the living material which 



* As Meldola insists, this general acceptance was in the first instance largely due to the writings of Herbert 

 Spencer: " AVe are now prepared for evolution in every domain. * * * As in the case of most great gen- 

 eralizations, thought had been moving in this direction for many years. * * * Lamarck and BuGon had 

 suggested a definite mechanism of organic development, Kant and Laplace a principle of celestial evolu- 

 tion, while Lyell had placed geology upon an evolutionary basis. The principle of contmuity was begin- 

 ning to be recognized in physical science. * * * It was Spencer who brought those independent lines 

 of thought to a focus, and who was the first to make any systematic attempt to show that the law of develop- 

 ment expressed in its widest and most abstract form was universally followed throughout cosmical processes, 

 inorganic, organic, and superorganic."— Op. cit., p. 14. 



