LIFELESS AND LIVING PARTICLES. 69 



Non-living Particles of Matter contrasted with Living 

 Particles. It is desirable to consider in this place whether 

 anything may be learnt by comparing very minute lifeless 

 particles with very minute living particles under very high 

 magnifying powers. 



A little inorganic matter of any kind, but in a state of 

 very minute subdivision may be subjected to examination. 

 Take for example a little of the deposit of phosphate of 

 lime which has been precipitated from a solution of a salt 

 of lime by the addition of a soluble salt of phosphoric acid. 

 Now what is observed when this fine precipitate is placed 

 under the microscope ? Only a number of minute granules 

 or dots possessing no definite form and exhibiting no indica- 

 tions of structure. If the deposit be examined by the 

 highest powers at our command, the apparent size of the 

 particles will indeed be increased, and others which were 

 previously invisible will be brought into view but no 

 appearance of structure can be recognized. Spots they 

 appeared under moderately high powers, and mere spots 

 they remain under the highest magnifying powers we can 

 obtain. Certain movements are however to be observed. 

 Each little particle revolves and oscillates in the fluid. 

 These movements have been termed molecular, and were 

 first described many years ago by Robert Brown. We know 

 that the particles under observation are inorganic, and we 

 are therefore quite sure that the movements we witness are 

 due to physical forces alone. 



Next let us take a small fragment of dead animal or 

 vegetable matter, and place it in a few drops of pure water 

 on a glass slide, and examine carefully the fluid under the 



