MICHIGAN ACADEMY OF SCIENCE. 19 



armed him for a defence of his conehisious l)a^ed hirgely upon deduction 

 and permitted him to leave speculation in the background. 



It is always a thankless task to call the roll and appraise the results of 

 any body of workers, but certain men have stood out so prominently in the 

 development of the Neo-Lamarckian school that we may name them without 

 fear of contradiction. Cope, Ryder, Scott and Osborn among the vertebrate 

 paleontologists, Dall and Hyatt among workers on invertebrates and Lester 

 Ward of the paleobotanists; the work of these men may be taken as epito- 

 mizing the growth of Neo-Lamarckism in America. Of these Cope. Ryder, 

 Dall and Hyatt may be regarded as the founders of the school. In 1SS6, 

 Hyatt read his paper "On the parallelism between the different stages of 

 life in the individual and those of the entire group of the Molluscan order 

 Tetrabranchiata " in 1880 he defined his ideas more clearly in two papers 

 "Upon the effects of gravity upon the shells of animals" and "The genesis 

 of Tertiary species of Planorbis at Steinheim." In 1890 Dall jmblished his 

 paper on the "Dynamic Influences in Evolution." In 1871 appeared Ryders 

 paper "On the laws of digital reduction" and in 1879 another "On the 

 mechanical genesis of tooth forms." other papers from this author appeared 

 at intervals until 1890 upon similar themes. Copes Origin of the fittest 

 appeared in 1887 and the Primary Factors of Evolution in 1896. These 

 books were in large part republications of essays printed at earlier dates. 



These papers represent a distinct stage in the development of the Neo- 

 Lamarckian school for they insist on the origin of variations from the 

 effect of strains set up Idv the environment or by the effort of the individual 

 and on the preservation of these variations by natural ^^ielection. This 

 is, perhaps, Neo-Lamarckism in its purest phase. 



The continued stuches of long phylogenetic lines such as the labors of the 

 American paleontologists Avere perfecting led to the recognition of the fact that 

 Neo-Lamarckism as defined above was not competent to answer all questions 

 which arose and so there has been a gradual development of the present 

 phase of the theory entertained by the so called American School. 



Osborn in an address before the American Society of Naturalists in NeAV 

 Haven in 1906 described what he called the jour inseparable factors in evolu- 

 tion — Ontogeny. Heredity, Environment and Selection. He expressed 

 these in the formula OxH xE xS in which the X sign may be read "influenced 

 by and influencing." We may review Osborns pa])er as a convenient way 

 of introducing the new phase of Neo-Lamarckism. S need not be discussed, 

 for according to the Neo-Lamarckian school it can not be admitted as a 

 factor having to do with the origin of variations, though nearly all powerful 

 in their preservation. 



The Buffonian factor of evolution may be expressed in the formula In- 

 ExoXhXs. Emphasizing, the predominant effect of the environment. 

 Dall in his paper on the Dynamic Influences of Environment said: "The 

 environment stands in relation to the individual as the hammer and the anvil 

 to the blacksmiths hot iron. The organism suffers during its entire ex- 

 istence a continuous series of mechanical impacts, none the less real because 

 invisible." As Merriam said these are bold words but weighty and well 

 worth considering. 



The Lamarckian factor may be represented by the formula, OxhxeXs, 

 i. €. The development of a character during the life of the individual 

 and the establishment of this character by heredity. 



But Lamarckism has failed to answer several questions which have been 

 proposed, 



