PACKARD. — INHERITANCE OF ACQUIRED CHARACTERS. 389 



suits in a profound modification of the physical, intellectual, and moral 

 nature of the suhject operated upon. 



4. It has not yet been satisfactorily disproved that new characters, 

 or the tendency to the heredity of such characters, are not the result 

 of a change of external environment, however slight. This appears to 

 be the primary cause of all changes in organisms. 



5. As blastogenic or congenital characters are not invariably trans- 

 mitted, with much less reason may somatogenic or acquired characters 

 be invariably transmitted, especially at the present da}'. 



6. The transmission of acquired characters may have been more 

 frequent and regular in early geological ages, during the period of 

 the origin of family, ordinal, and class ancestral types, and when such 

 forms were more plastic than now owing to more wide-spread and 

 rapid changes in the physical geography of the earth's surface than 

 occur at present. During paheozoic times somatogenic characters may 

 have greatly preponderated over blastogenic characters ; for at certain 

 critical periods iu geological history there were wide-spread extinc- 

 tions of certain species of plants and animals, followed or accompanied 

 by profound modification of others, which led to the origination of 

 new types. Hence a study of the origin and subsequent modification 

 and disappearances of organs in series of extinct animals will afford 

 weighty facts. 



7. If congenital characters are the only ones which can be inherited, 

 they must have in the beginning originated from those acquired during 

 the lifetime of the individual, or if not in the first, in the second or 

 third, or a later generation. 



8. Can we always draw the line between congenital and acquired 

 characters ? It seems to us to be often not only very difficult, but well- 

 nigh impracticable, except in animals with a metamorphosis. 



9. The results of the cultivation of fruits and of the domestication 

 of animals, as well as the experiments of Brown-Ssquard, Bert, and 

 others, strongly suggest that the characters acquired during the life- 

 time of such organisms are capable of transmission. 



10. If there were no such thing as the transmission of characters, 

 either anatomical, physiological, or mental, originating during the life- 

 time of an organism, how should we have any evolution resulting in 

 the different groups of organisms ? Does not the denial of the fact 

 of transmission of acquired features either in the past or present cut 

 away the support for either phase of evolution, whether Lamarckism 

 or Darwinism? 



If the processes of heredity have to he begun over again with the 



