i 7 6 THE POPULAR SCIENCE MONTHLY. 



give, but a reference to those facts connected with it that are of chief 

 interest to you. I must bear in mind that this is an institute of cler- 

 gymen seeking information on a topic which they consider to have a 

 bearing on their pursuits, and that it is from a corresponding point 

 of view that I must present it. 



Two explanations have been introduced to account for the origin 

 of the assemblage of organic beings, plant and animal, that surround 

 us. These are conveniently designated as the hypothesis of Creation 

 and that of Evolution. 



The hypothesis of Creation asserts that Almighty God called 

 into sudden existence, according to his good pleasure, the different 

 types of life that we see. This hypothesis has an ecclesiastical form, 

 that the world, with all its various animals and plants, was created 

 about six thousand years ago. The work was completed in six days, 

 and was perfect, needing no improvement. At the close of each day 

 the Almighty surveyed what he had done, and pronounced it very 

 good. He brought all the animals thus made before Adam in the 

 garden of Eden to receive their names. There was nothing more 

 necessary, and on the seventh day he rested. 



The hypothesis of Evolution asserts that from one or a few origi- 

 nal organisms all those that we see have been derived, by a process 

 of evolving or development. It will not admit that there has been any 

 intervention of the divine power. 



The former of these hypotheses considers each species as indepen- 

 dent of all the others; the second considers them as inter-related. 

 Creation reposes on the arbitrary act of God : Evolution on the uni- 

 versal reign of law. 



The hypothesis of Evolution in its scientific form presents three 

 factors: 1. Heredity; 2. Environment; 3. Adaptation. By heredity 

 is meant the tendency manifested by an organism to develop in the 

 likeness of its progenitor. By environment, the sum total of the phys- 

 ical conditions by which the developing organism is surrounded the 

 ambient world. By adaptation, the disposition so to modify as to bring 

 an organism and its environment into harmony. This may be accom- 

 plished either by progression or retrogression. 



As to the origin of organisms, it withholds, for the present, any 

 definite expression. There are, however, many naturalists who in- 

 cline to believe in spontaneous generation. In its most improved form 

 it occupies itself with two classes of problems, the direct and the in- 

 verse, considering in the former the effect of the environment on the 

 organism, and in the latter deducing from the organism the nature of 

 the environment. Thus Schleiden gathers from the structure of the 

 stems of certain pine-trees the distribution of climates at the time of 

 their growth; and the ancient geographical connections of Madagas- 

 car and of Australia may be thus ascertained from their fauna. 



