HEREDITY OF ACQUIRED CHARACTERS 185 



mitting an organism to a certain set of conditions, and thus 

 causing it to acquire certain characters, so to modify its repro- 

 ductive organs, that the same characters will appear in its 

 offspring as the result of the application of a different and 

 simpler stimulus ? " ^ 



He then sums up "the argument as it at present stands : 

 (i) A change in conditions cannot affect the next generation 

 unless the reproductive organs are affected ; (2) from a con- 

 sideration of the facts of the case, it is almost inconceivable 

 that the effect produced upon any organ of a given organism 

 by a change of conditions should so modify the reproductive 

 organs of that organism as to lead to a corresponding modifica- 

 tion in the offspring without the latter being exposed to the same 

 conditions [my italics] ; (3) the only effects which are certainly 

 known of changed conditions upon the reproductive organs 

 are {a) the production of sterility ; {b) an increase in genetic 

 variability." 



Of these three propositions the first and second are 

 hypothetical. 



Would it not have been better to study Nature to see what 

 happens ; and then argue from facts, so as to discover whether 

 the reproductive system does or does not bring out acquired 

 characters in the offspring ? 



In the first place, to demand the re-appearance of characters 

 acquired by an adult parent, i.e., during its growth from infancy 

 to maturity, in the first getieration, is to ask for what Nature 

 does supply in full measure ; as for example in experiments 

 with the seed of wild parsnips, carrots, radishes, etc. Not 

 only does the increase in the size of the root " acquired " by 

 the first seeds sown reappear in the next, but it becomes 

 intensified ; i.e., of course, when sown in good garden soil. 



But to ask if the acquired characters appear when the 

 offspring is removed to another environment is simply to ask 

 Nature to undo all that the parent had done for the next 



1 It is not very clear what is meant by "a different and simpler" 

 stimulus. 



