ii LIVING MATTEE 51 



formulated in regard to the elementary vital activities, which are 

 all centred in metabolism. Both the reproductive capacity, by 

 which the hereditary tendencies are rapidly completed, and the 

 evolutionary capacity, by which the creative tendencies slowly 

 develop, are founded upon the metabolic processes of living 

 protoplasm. 



The same difference that we have seen to exist between 

 automatic activity as depending essentially on internal impulses 

 and tendencies, and reflex activity as due to external stimuli, 

 exists between Nagelisni and neo-Lamarckism. 



Starting from the psycho-physical theorem that conscious 

 psychical phenomena are the introspective aspect of correlative 

 physiological excitations, it is not too bold to assume that 

 unconscious physiological phenomena likewise have a psychical 

 aspect which is not clearly revealed to introspection, although it 

 helps to build up the content of consciousness. With this premise, 

 it seems reasonable to admit with Hering that ontogenic pheno- 

 mena are the correlatives of an unconscious memory inherent in 

 the protoplasm ; just as phylogenic phenomena might be considered 

 the correlatives of an unconscious formative imagination. 



Weisniann (in 1892) attempted a sort of reconciliation between 

 Darwinism, Lamarckism, and Nagelism by assuming that the 

 action of external causes might be fixed in the species, and become 

 hereditary, if the said action were exercised on the plasma of the 

 germinal cells. The modifications suffered by these would manifest 

 themselves in the embryo and the adult individual, and would be 

 transmitted to the descendants. In this way what Weisniann 

 calls germinal selection would become possible, in which the action 

 of external agents, combined with natural selection, would deter- 

 mine the origin of new species. 



These, however, are merely ingenious abstract speculations, 

 which more or less successfully disguise our impotence to determine 

 in any precise and accurate manner the relation between the action 

 of external causes and the reaction of internal causes, manifested 

 in the development of a morphological process. 



De Vries (1901) thought to escape from the many and 

 insuperable difficulties of the hypotheses we have been examining 

 by his Theory of Mutations, according to which new species 

 originate not in a continuous variation, but in discontinuous 

 variations, by sudden leaps which he termed mutations. In 

 certain moments of the life of the species, under special conditions, 

 some individuals may unexpectedly assume a series of new 

 characters, differing from those possessed by their progenitors, and 

 these characters might be hereditary. 



Many well-known facts in the history of plants and domestic 

 animals seem to prove the sudden origin of new forms, as supposed 



