190 



LIVING AND NON-LIVING PARTICLES. 



the one with inorganic matter suspended in water, and the 

 other with organic matter and water, may now be placed in 

 a warm room under similar conditions for a few hours, 'care 

 being taken that light and air have free access to both 

 specimens, and that any fluid lost by evaporation be sup- 

 plied. At the end of five or six hours the slides should be 

 again examined. 



The one containing the inorganic deposit of phosphate 

 of lime shall be called A, and the other slide shall be B. 

 No change has taken place in A. There are the little life- 

 less particles still moving as before in the fluid in which 

 they are suspended. Some of them indeed may have 

 become aggregated together so as to form little collections, 

 but beyond this there appears to have been no change. 



Next let the other slide B, be examined. The fluid 

 which, when first seen, was perfectly clear, is now found to 

 contain a number of exceedingly minute dots, points, or 

 granules, closely resembling the phosphate of lime granules, 

 and the newly formed particles manifest similar molecular 

 movements. If a little gum, glycerine, or any viscid material 

 be added to the particles on each slide, the molecular 

 movements are immediately suspended, and if the fluid be 

 diluted they recur. This indicates that the movements are 

 due to physical causes. The little particles which could 

 move freely in such a limpid fluid as water, are prevented 

 from moving if the fluid in which they are suspended be 

 rendered viscid. 



Let both slides be again set aside for a few hours longer. 

 It will be found that the inorganic matter upon the slide A 

 has undergone no change. But the case is very different 

 with regard to slide B. The granules that have appeared in 



