224 PROCEEDINGS ,0P THE AMERICAN ACADEMY. 



are that the progressive steps of the evolution of the primitive types of 

 organisms took place with a rapidity unexampled in later ages. If the 

 laws of bioplastology are ti-ue, the evolution of these forms must have 

 occurred more quickly than those of their descendants, except some iso- 

 lated phylogerontic types and phylopathic forms.* Man being the most 

 remarkable of these phylogerontic types, we can at once realize what 

 this statement means. If his remains in all their vastness were a part of 

 geological history, and could be contemplated separated from the artificial 

 halo of idealism, it would be seen that they were the direct results of the 

 law of tachygenesis acting upon the basis of a simian organization and 

 exceptional, as compared with other phylogeronts only because of this ex- 

 ceptional basis. 



All inferences with reference to the length of time that life has existed 

 upon the earth are consequently defective, since, as far as known to the 

 author, the}^ do not take into consideration this law of variable pro- 

 portions of time in evolution of organisms at different stages in their 

 history. 



* The plirase ' evolution by saltation ' has been used for the sucWen appearance 

 of divergent types by several authors, first by Dr. W. H. Dall; but this seems to 

 me to be simply a mode of expressing a general fact, or series of facts that occur 

 everywliere, and in all series more or less through the action of the law of tachy- 

 genesis. 



