CHAPTER III 



ON SOME PROPERTIES OF CRYSTALS, WITH OBSERVATIONS ON THEIR 



MODE OF ORIGIN AND ON THE MODE OF APPEARANCE 



OF LIVING UNITS 



JUST as the form and properties of the crystal are to be taken 

 as the natural outcome of the properties of its constituent 

 molecules under the influence of its environment, so are the 

 forms and properties of simplest organisms to be considered as 

 the natural outcome of the properties of their molecules, entering 

 into combination under the influence of their environing conditions. 



Views analogous to these have been more or less fully expressed 

 by many writers. The essential similarity in the laws regulating 

 crystalline and organic forms was even suggested by Maupertuis in 

 1744.' Crystals and organisms were spoken of by Burdach" as 

 statical and dynamical aggregates respectively. The formation of 

 organisms was, moreover, in 1836, definitely compared by Schwann 

 to the formation of crystals. Cells, which were then believed to 

 be the types of all primordial organisms, were thought by him to 

 owe their form to a process essentially similar to crystallisation ; 

 the chai-acteristic shapes being due, in the case of cells, to a 

 peculiarity in the nature of the substance of which they were 

 composed. But it was in 1863, in the first edition of his "Principles 

 of Biology," that this relationship was most fully pointed out by 

 Herbert Spencer, believing as he did that the structures and shapes 

 of lower organisms are the results of the ' polarities ' of their con- 

 stituent organic units, under the continually modifying influence of 

 external conditions. To his views on this subject we shall sub- 

 sequently refer in some detail, so nothing more need be said at 

 present. 



Although saline materials so frequently aggregate into crystalline 

 shapes when they emerge from the state of solution, still, in many 



' See Milne-Edwards in " Physiologic at Anatom. Comp." t. viii. p. 247. 

 ' " Traite de Physiologie " Transln., 1839, t. iv, p. 129. 



