6oo THE WONDER OF LIFE 



the case of parallel induction, it seems that the environ* 

 ment works indirectly, through the mediation of these 

 (not living) products, which when once formed are not 

 immediately got rid of, but are passed on passively included 

 in the protoplasm of the gamete '. Some (not living) 

 product is included in the egg, passes passively into the 

 body which develops from the egg, and thus produces on 

 the body the same effect as it produced on the body of the 

 parent which acquired the character in question. 



Dr. Agar sums up the question of transmissible environ- 

 mental effects as follows: (1) A changed environment 

 (in its widest sense) may produce a visible modification in 

 the body indirectly by altering the nature of the metabolic 

 products included in the living protoplasm. These in 

 turn react with the protoplasm, and therefore effect changes 

 in its product, the body. (2) Whenever the environment 

 acts simultaneously on body and gonad a similar alteration 

 in metabolic inclusions of somato- and germ-plasm takes 

 place. (3) These metabolic substances included in the 

 germ-cell naturally pass into the developing body, which, 

 therefore, shows the same modification as its parent did, 

 even though removed from the environment in question. 

 (4) These substances may produce a powerful effect, though 

 present only in minimal quantities. (5) They may be of 

 such a nature as to stimulate the formation of antibodies, 

 thus causing a reaction in later generations. 



It is probable that many biologists of to-day would be 

 relieved to find that there is much more truth in Lamarckism 

 than Charles Darwin thought there was when he said ' Hea- 

 ven forfend us from such Lamarck nonsense '. We have 

 taken the most scientific investigation we know of that 

 bears on this question, and it does not seem to strengthen 



