ANIMAL BEHAVIOR. 



3*3 



changes which the nervous elements undergo can be transmitted 

 from father to son. . . . The assumption of the inheritance of 

 acquired dispositions or tendencies is inevitable if there is to be 

 any continuity of evolution at all." 



3. Darwin s Refutation of Lamarck's Theory. Although 

 Darwin dwelt at some length on the points of resemblance 

 between habits and instincts, and although he thought it 

 possible that habits could sometimes be inherited, it should 

 be remembered that he was the first to show conclusively 

 that " the most wonderful instincts with which we are ac- 

 quainted, namely, those of the bee hive and of many ants, could 

 not possibly have been acquired by habit " (Origin of Species, 

 p. 202). Indeed, it was he who first found in the case of neuter 

 insects a refutation of Lamarck's doctrine of inherited habit, 

 and at the same time a demonstration of the high efficiency of 

 the principle of natural selection. Darwin concludes his chapter 

 on instinct with these memorable words : 



" The case of neuter insects, also, is very interesting, as it proves 

 that with animals, as with plants, any amount of modification may be 

 effected by the accumulation of numerous slight, spontaneous varia- 

 tions, which are in any way profitable, without exercise or habit hav- 

 ing been brought into play. For peculiar habits confined to the workers 

 or sterile females, however long they might be followed, could not possibly 

 affect the males and fertile female, which alone leave descendants. I am 

 surprised that no one has hitherto advanced this demonstrative case of 

 neuter insects against the well-known doctrines of inherited habit, as 

 advanced by Lamarck" 



What could more forcibly illustrate the importance of crucial 

 cases than just this work of Darwin's on the instincts of neuter 

 insects ? Here a conclusive test is reached, and no theory of 

 the origin of instinct can stand that disregards it. If habit 

 cannot possibly have had anything to do with the origin of such 

 typical instincts, then we should at least be very cautious in 

 appealing to it in any case. We certainly do not want two 

 theories to account for the same phenomenon, if one will suffice. 

 If the theory of inherited habit is certainly false in a single 

 case, it must be deemed false in every case, until at least it has 

 been shown that some cases cannot be explained without it. Is 



