178 Inheritance of Acquired Characters 



adapted to its purpose, a thing which each individual does 

 only once and from the most ancient times has done 

 only a single time in all its life." 139 



2. The second group of facts controverting the 

 inheritance of acquired characters is furnished, accord- 

 ing to Weismann, by the parts which have only a passive 

 function, "in so far as they show that they also become 

 rudimentary and finally disappear if they cease to be 

 used and are not necessary for the preservation of the 

 species. They show that the process of disappearance 

 which the Lamarckians attribute to the inheritance of 

 the direct effects of non-usage cannot be due to this 

 cause, since here the organ in question does not exert 

 any physiological function and so there are of course 

 no effects of such function in the individual life. To 

 this category belong for example the colors of animals, 

 which become unstable when they are no longer needed 

 for protection or as a means of recognition; here also 

 belongs the deterioration of the chitinous cuirass of 

 various crustaceans and insects which thrust one part 

 of their body into protective envelopes." 14 



3. The third argument against the inheritance of 

 acquired characters is that constituted by the neutral 

 individuals among bees, ants, and termites which, accord- 

 ing to Weismann, show that all the adaptations whether 

 positive or negative, isolated or co-ordinated, that are to 

 be observed in propagating individuals, appear also in 

 individuals which do not propagate at all and which 

 therefore do not transmit anything. 141 



"'Weismann : Neue Gedanken zur Vererbungsfrage. Eine Ant- 

 wort an Herbert Spencer. P. 61 62. 

 140 Weismann : Ibid. P. 6263. 

 141 Weismann: Ibid. P. 66. 



