HEREDITY 493 



few known facts which lend support to this view, but it 

 seems premature to foreclose the question by any dogmatic 

 denial of the possibility that individually acquired modifica- 

 tions can leave representative imprints on the organisation, 

 or, as some would say, on the unconscious memory of the 

 germ-cells. It is possible that an increase of knowledge will 

 show us that there is some hidden truth in the Lamarckian 

 position; but the facts do not point that way at present 

 Deserving of consideration here are the remarkable facts of 

 cellular habit or momentum in metabolism, expounded nota- 

 bly by Prof. J. G. Adami (1918, p. 55 and p. 166). Pro- 

 fessor Adami calls attention to facts like the following. Once 

 the cells of the body of a rabbit have got accustomed to pro- 

 ducing a counteractive or anti-toxin to ricin (a poison from 

 the castor-oil plant), they may go on producing this anti- 

 ricin for weeks or months after the original stimulus. There 

 is an organic momentum. In the horse a single toxin unit 

 of tetanus can lead in the process of immunisation to the 

 production of 1,000,000 anti-toxin units. A cold in the head 

 may continue for weeks after the causative agent has dis- 

 appeared, and thorough sterilisation of the nose has been 

 effected. The cells form a habit, it may be an entirely new 

 habit, and it lasts, " an acquired cell variation becoming, if 

 I may so express it, converted into a cell-heredity ". But the 

 difficulty is to pass from such cases to the generations of 

 multicellular animals. 



(2) The known facts point to the conclusion that the or- 

 ganic materials of progress are supplied from within, from 

 the fountain of change that there is in the germ-cell. If 

 the metaphor be permissible, and we cannot get beyond meta- 

 phors yet, the germ-cell is the blind artist whose many in- 

 ventions are expressed, embodied, and exercised in the de- 



