From the Unconscious to the Conscious 



of Giard and Le Dantec in France, are Lamarckian 

 systems. 



Packard has summed up the causes of variation as 

 seen by him as follows. 



Neo-Lamarckism acknowledges and unites the 

 factors of the school of Saint Hilaire and those of 

 Lamarck as containing the most fundamental causes 

 of variation ; it adds to these geographical isolation, 

 or segregation (Wagner and Gulick), the effects of 

 weight, of currents of air and water, the mode of 

 life, fixed, sedentary, or per contra, active ; the results 

 of tension and of contact (Payder, Cope, and Osborn), 

 the principle of a change of function as bringing 

 about the appearance of new structures, (Dohrn), the 

 effects of parasitism, commensalism 1 and symbiosis, 2 

 in short, of the biological environment, as well as 

 natural and sexual selection and hybridism. In 

 fine, all conceivable primary factors. 



Cope has made a special endeavour to explain the 

 appearance of variations by the action of these primary 

 factors. He refers variations to two essential causes. 

 The first is the direct effect of the environment, and 

 to all the factors above enumerated Cope gives the 

 general name ofphysiogenesis. The second is the influence 

 of the use or disuse of organs, the physiological reactions 

 produced in the animal in response to exciting causes 

 in the environment. Cope calls this kinetogenesis. 



This second cause would be of the first importance, 

 and Cope brings this out by his study of palaeontology. 

 He adduces innumerable examples in support of his 

 thesis. One of the best known is the formation of the 

 foot by adaptation to speed, in plantigrade, and more 

 especially digitograde, quadrupeds, with the characteristic 



1 Identity of food. * Living together. 



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