BIOLOGICAL INVESTIGATIONS. 147 



which necessarily take place through action that proceeds from 

 within outwards. The fact that it takes an appreciable time 

 for an organism to receive an impression, and to begin to react 

 by its own efforts in the presence of an irritating substance, or 

 to begin to change in response to new surroundings, and that 

 its corresponding movements and modifications are suitable, 

 shows this with a simple directness not characteristic of other 

 explanations of the origin of variations. It is not intended to 

 defend this theory, which originated with Lamarck, and was 

 subsequently, but independently, restated by Cope and the 

 author of this lecture, but simply to point out some of the 

 inevitable failures of reasoning due to the neglect of the con- 

 sideration of the internal reactions of organisms.^ 



Experimental biologists are very apt to neglect this factor in 

 their conclusions, and consequently either invert the natural 



1 The general impression that neolamarckism implies belief in action of the 

 surroundings is true only so far as these act as stimuli, or may be proved to act 

 directly upon organisms. Neolamarckism, or, better named, the Dynamical School 

 of Biology, does not reject the Darwinian hypothesis when the struggle for exist- 

 ence or selection of any sort is recognized as a result of evolution, as a secondary 

 cause tending to the preservation and perpetuation of differences after these have 

 been originated by fundamental causes. The dynamical hypothesis can be shown 

 to be inoperative only by proving that the internal mechanism of motion in 

 organized beings is ineffectual to produce variations. It deals with the imme- 

 diate origin of variations through internal reactions, and is really open to any 

 explanations of the subsequent conduct and preservation of these that can be 

 proven. 



Since this lecture was delivered, I have had the pleasure of receiving a very 

 profound and interesting . printed lecture of Dr. C. O. W^hitman, on Animal 

 Behavior, biological lecture at Woods Holl Laboratory, 1898. Although he takes 

 up a position adverse to those advocated in this lecture, this author really does 

 seriously consider some of the neglected theories usually omitted by students of 

 existing biological phenomena, or neobiologists, and so far his lecture meets the 

 general criticisms offered here. It appears to me, however, after reading this 

 and other essays, that a large part of the differences between the schools that 

 believe in the inheritance of acquired characters lies in the different definitions 

 of what is meant by acquired. Again it is, perhaps, as stated by Whitman, very 

 difi&cult to find a character, or instinct or habit, which will meet his requirements 

 among the habits of existing organisms. Habits "having no hereditary basis 

 predisposing to them" (Whitman, p. 314) are as hard to find in existing complex 

 or fixed organisms as characters having no similar basis. My own definition of 

 an acquired character is that it is not present in the more primitive forms of the 

 same phylum, and tends to occur first in a comparatively late stage of the ontogeny 

 (see " Phylogeny of an Acquired Characteristic," op. cit.). 



