THE PATH OF EVOLUTION 



tempt the slightest sketch of the progressive com- 

 plexity of structure that attends each upward step in 

 the order of Animal Life would require this article 

 to be a treatise oh comparative physiology and zoology. 

 To examine the dividing line between that which has 

 not life and that which has, to note the first occurrence 

 of organization, and to observe the way and the only 

 way in which life is formed a resultant from a pre- 

 existing life of a parent has been our purpose. It 

 is better observed in the vegetative world than it can 

 be in the animal. The reproduction of life from the 

 parent cells, and the physiological changes that the 

 microscope reveal, are essentially alike in plants and 

 in animals, and, from obvious reasons, are better dis- 

 cussed, as they have been here, .in relation to the 

 former. The analogy between the germination of a 

 seed and the development of the bird from the egg 

 may, however, be momentarily considered. 



The process in the formation and growth from the 

 germ is essentially the same in the viviparous as it is in 

 the oviparous animal, yet it can be far better observed 

 in the latter than it is possible to do in the former in- 

 stance. A close analogy exists in many ways be- 

 tween the seed of a plant and the egg of an animal. 

 As has been already stated, the greater portion of a 

 seed, a grain of corn for instance, consists of material 



provided for the subsequent nourishment of the germ, 



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