Royal Microscopical Society. 241 



the various states of matter, such as gaseous fluid, viscous and soHd, 

 of various degrees of density. When the sihca passes from the 

 gaseous to the amorphous soHd state, it may be that the rushing 

 and clashing together of molecules is too confused for crystalhza- 

 tion, or for the regularity required in organic patterns. A certain 

 measured and rhythmical retardation may be necessary for the for- 

 mation of crystals, or organic patterns ; and in the case of these 

 silica films the violent reaction between the sihcic fluoride and 

 water is moderated by the glycerine. No one supposes he is making 

 diatoms by Schultze's process, nor organic cells by the method 

 now described; but some light may be thrown upon processes 

 that do belong to organic hfe, by noticing how the presence of 

 certain retarding elements may cause crystalline or other forces 

 of aggregation to deposit matter in the shape and quantity required 

 for the structure of living beings. 



In some of the slides minute crystals have been found, mostly 

 isolated prismatic needles, or radiating groups of them ; also some 

 rhomboid tables, differing little from square forms. In one case a 

 small octohedral column with a flat top was seen. All the thicker 

 films act slightly on polarized light, and so do most of the crystals, 

 but not all, probably from some not being in the right position. 

 These crystals are most likely silicates of minute portions of alkahes 

 accidentally present. Their fewness and extreme smallness would 

 render chemical analysis impracticable. In viewing them with 

 polarized light it is advisable to place the polarizer underneath 

 the achromatic condenser, and observe them with ith and higher 

 powers. 



