ANIMAL BEHAVIOR. 319 



throutrh the cerebrum. Instincts and reflexes, however, have 

 their seat for the most part elsewhere. The tracts of very few 

 of them are found in the cortex of the hemispheres. It is 

 chiefly in the lower parts of the brain and spinal cord that the 

 associations and coordinations corresponding to instincts and 

 reflexes have their seat. When the comparative anatomist 

 investigates the relative size of the hemispheres in verte- 

 brates (especially in amphibians, reptiles, birds, and mammals), 

 a very evident increase in size is observed which apparently 

 goes hand in hand with the gradual gain in intelligence. In 

 the course of long phylogenetic development, during which the 

 hemispheres have gradually attained their greatest dimensions, 

 they have constantly been the organ of reason and the seat 

 of acquired association. If, then, habit could become instinct 

 through heredity, it is probable that the cerebrum would, in 

 much greater degree than is the fact, be the seat of 

 instinct.' " 



The stronghold of the Lamarckian view is Paleontology. 

 It is here that the doctrine of acquired characters, or ctetology 

 as Professor Hyatt calls it, has been nearly as unyielding as the 

 fossils to which it adheres. But a new light seems to be pene- 

 trating even here under the name of "organic selection." 

 This idea, first formulated by Professor Baldwin, but almost 

 simultaneously and independently reached by Lloyd Morgan 

 and Professor Osborn, is, that adaptive modifications are not 

 transmissible, but that they have, nevertheless, acted as tJie 

 fostering nurses of congenital variations, since organisms sur- 

 viving through them would carry forward to the next genera- 

 tion such congenital variations as happened to be coincident 

 with them. It may be, perhaps, a fine question to determine 

 whether so-called " adaptative modifications," which really have 

 selection value, are not themselves the coincidents of con- 

 genital bases. Be that as it may, the conversion of so eminent 

 a paleontologist as Professor Osborn to the selection theory is 

 all the more significant on account of the prominent part he 

 has taken in defending the Lamarckian idea. 



