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.” °° 
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.” 1*° 
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.1*4 
*°Weismann: Neue Gedanken zur Vererbungsfrage. Eine Ant- 
wort an Herbert Spencer. P. 61—62. 
*°Weismann: Ibid. P. 62—63. 
Weismann: Ibid. P. 66. 
