182 ROYAL SOCIETY OF CANADA 



eies." It was first given in the " Variation of iVnimals and Plants under 

 Domestication " which appeared in 18G8. It at omce met criticism on 

 all sides even from some of those who were staunch supporters of Dar- 

 win's views on Evolution generally. It did indeed win favour for a time, 

 but it is now regarded as merely an interesting speculation which lias 

 had its day. 



The reason for this is not far to seek. The theory was advanced 

 to explain what was generally accepted as a fact. It was commonly be- 

 lieved that anatomical or structural characters acquired by an animal 

 dining its own life througii injury, mutilation or extraordinary use or 

 disuse of any organ or structure, could be transmitted to its own imme- 

 diate offspring. It was not that any one postulated such a result in 

 every case, for the ordinary individual holding such a view was prepared 

 to admit that an animal with cropped ears would not necessarily in 

 every case produce offspring with ears different in shape from that 

 normal in the species, and that, further, a dog or a cat deprived through 

 an operation of its tail did not necessarily produce tailless pups or kit- 

 tens. It was, however, held that when, after a parent form had under- 

 gone a structural alteration in one of its organs through an injury, one 

 or more of its offspring manifested a similar alteration, the result was 

 due to inheritance. Why such alterations in the parent form were not 

 always followed by similar changes in the offspring was not explained, 

 nor was an attempt made to do so. All that was in concern was the oc- 

 casional transmission of such characters. 



This belief appeared to be supported by the results of observations 

 on plants and animals in the state of domestication. It was recognized 

 that both plants and animals when in an artificial environment mani- 

 fest an extraordinary variability, and that unusual characters appearing 

 under these conditions could by artificial selection in breeding be trans- 

 mitted to the offspring. Evidence of this was found in garden flowers, 

 in pigeons and other domestic animals, some of which have developed in 

 this way such differences in character as to make them appear as if they 

 represented new species. Such unusual characters were supposed to be 

 due to the direct action of the food or of the environment or of both the 

 food and the environment. 



The effect of use or disuse of an organ, or of the functional stimula- 

 tion of parts in an animal form, in influencing the character of its off- 

 spring was of cardinal importance in the theory of Lamarck advanced 

 exactly half a century before the " Origin of Species " appeared. Dar- 

 win also in the latter work discussed the results of use and disuse of parts 

 and showed, as has been done again and again since quite clearly, that 

 we must recognize that use and disuse are in the history of a species 



