904 



SCIENCE 



[N. S. Vol. XXXrv. No. 887 



oped into human kind began. And this, 

 for each of us, is not a figure of speech, 

 but the plain literal truth. An unlimited 

 microscopist could have followed with his 

 eyes my course, and your course, down 

 through countless ages, never losing sight 

 of the material organism for an instant, 

 just as our colleague. Dr. Woodruff, fol- 

 lows day by day his thousands of genera- 

 tions of Paramecium. I was in actual ma- 

 terial existence as a living organism, and 

 indeed thousands or millions of years old, 

 when the pyramids were built, and my un- 

 limited microscopist could give my history 

 from that time to this without a break. 

 "What marks has that long history left on 

 my personality and character? 



When in England for the first time last 

 summer, I was struck with the familiarity 

 of things strange; by a feeling as if I had 

 returned to my old home. The great 

 things of England seem the working out, 

 the carrying to a limit, as it were, of the 

 tastes that live in me and mine, while the 

 great things of other countries are the 

 revelation of a spirit to me relatively new 

 and foreign. It may not have been an ex- 

 planation, but it was the truth when I 

 said to myself at that time : I have indeed 

 lived in England many hundred years, 

 much longer than I have lived in America. 

 During the thousands of years of my exist- 

 ence I have had experience of many lands 

 and many people. But of the last thous- 

 and years of my life, I have spent all but 

 a couple of centuries or so iu England. 

 During that time I have taken part in the 

 growth and development of many an Eng- 

 lishman, and of many an Englishwoman. 

 And who can say that what I have grown 

 into in America has not been partly de- 

 termined by those habits of growth and 

 development that I acquired in that pleas- 

 ant English country — so that it is small 



wonder if things there fit me as if they and 

 I were made together? 



True, I was but a cell in the bodies of 

 those many Englishmen, but are we sure 

 that that statement has any real meaning; 

 that the cell — even the germ cell — is in 

 any sense a separate thing from the re- 

 mainder of the body? Must we not rather 

 conceive the body as a unit, in which all 

 parts share in the developmental processes 

 that occur? In those activities of organ- 

 isms that are most readily studied, the 

 principle holds that any process gone 

 through repeatedly and under stimulation 

 later takes place more readily and without 

 the original stimulus. There is no reason 

 why we should not expect this principle to 

 hold in development as well as in the other 

 activities of living things. If the body de- 

 velops as a unit and each cell in the body 

 takes part in that development, we have 

 the basis required for the operation of this 

 principle. After it has developed in a cer- 

 tain way a number of times under the ac- 

 tion of certain environmental stimuli, a 

 piece of the body, forming the germ cell, 

 would later develop in the same way with- 

 oi;t the same stimuli. What we have been 

 accustomed to develop into for the last sev- 

 eral thousand years, under the stimulus of 

 our old homes in Europe, possibly we de- 

 velop into here, so that our old homes fit 

 us as a mold fits the candle that was 

 shaped in it. 



The gradual formation of developmental 

 habits seems the only form of the idea of 

 inheritance of acquired characters that is 

 not opposed by any of the experimental 

 facts, that helps us to understand why so 

 many acquired characters are not in- 

 herited — since they are not produced by 

 the developmental processes of the organ- 

 ism; that fits all the recent cases which 

 give positive evidence for the inheritance 

 of acquired characters, and that is based 



