148 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



explain normal growth as well as so-called restitution : the 

 same thing happens all the time. In this respect crystallisa- 

 tion is a mere process of addition, in spite of so-called 

 restitution : the material of growth always cornes from the 

 solution in its specificity, and the typical form is completely 

 determined by the directed forces of all the minute particles 

 of the crystal. Knowing the forces of one particle and 

 knowing the physical conditions existing, we know that this 

 sort of growth must occur. Ultimately everything may be 

 reduced to some sort of molecular arrangement : the 

 specificity of the arrangement gives the specificity of the 

 distribution of forces of different intensity. A crystal thus 

 can be said to be " whole " in each of its parts, not only 

 " potentia " but " actu," and all processes of restitution in it 

 only relate to a change in the arrangement of such " wholes," 

 the result of it being not a proper " totality " in itself. 1 



I have said a little more about crystallisation than might 

 seem, to be necessary, because nowadays the analogies between 

 crystallisation and morphogenesis are being unduly pressed. 2 

 It is my opinion that there are analogies, nay more 



1 I have shown elsewhere (Arch. f. Entw.-inech. 23, 1907, p. 174) that 

 Przibram was wrong in saying that crystals are harmonious-eqnipotential 

 systems, according to my definition, because in some cases they are capable of 

 changing their exterior form after disturbances and producing a new smaller 

 proportionate whole. There is nothing whatever like a "prospective 

 potency " concerned in this process, as there is in organic harmonious 

 restitution : there is only a change of place going on among equal parts. 

 Even this change of place is not one single process, but the result of two 

 independent processes : something is taken away in one locality by the forces 

 of the medium, and something is added in another locality by the forces of the 

 crystal. I have never said that the mere fact of regeneration proves vitalism ; 

 but the special nature of the " systems " that form the basis of organic regenera- 

 tion does prove it (see vol. i. page 241 f.). 



2 Compare also the article by Hofmann in Annalen der NaturphHosophie, 

 7, 1908, p. 63. It seems to me that Hermann's argument cannot stand 

 against the analysis given in the text and in the preceding note. 



