CHAPTER VIII. 



TRACES OF UNITY IN ORGANIC AND 

 INORGANIC FORMS. 



THERE are many gaps in the barrier which has been 

 erected between the domains of organic and inorganic 

 nature. 



A very wide gap of this sort is to be found in many 

 of the solutions with which the microscopist has had so 

 much to do of late, for here it is often not a little 

 puzzling to know whether certain granules may be rudi- 

 ments of crystals, or of definite cellular growths like 

 Bacteria. Indeed, the gap here is so wide, and the 

 debateable ground on both sides so uncertain and far- 

 reaching, as to make it more than difficult to decide 

 where the barrier ought to be. 



Even in respect of growth a crystal may have some- 

 thing in common with the cell. At all events, many 

 difficulties have to be disposed of before it is possible to 

 say that the selective power by which a crystal appro- 

 priates to itself its proper material from the mother- 

 liquid is altogether dissimilar to that by which the cell 

 feeds and grows upon protoplasm. 



The crystal, moreover, is not necessarily bounded by 

 sharp angles and plain surfaces. Diamonds, for example, 

 have convex surfaces, and at times these gems differ 

 but slightly from perfect spheres. Curvatures are con- 

 stant in the grains of hail and in the plates of hoar-frost. 



G 2 



