176 Brunonian or Particle Movements. 



3. Movement of vibriones in putrid liquids. These must be vital. 

 '4. Movements undoubtedly vital in the molecules of the yelk. 



5. Movements in the pigment cells of the skin of the frog and 



chamelion, in fishes and other animals. 



6. Movements in the fibrillae of muscles, in pus, in mucus, the 



white blood corpuscles, and in the amoeba. 



These were what were called molecular movements in 1872, 

 and though they bore some superficial resemblance to each other 

 were even then differentiated as vital and as non-vital. 



At that moment we were on the verge of discovery of a new 

 science — Micro-biology or Bacteriology. Through the labours 

 of Pasteur in Paris, Koch in Berlin, I-ister in Edinburgh, and 

 other distinguished observers in other places, we were intro- 

 duced into what was practically a new world. A world invisible 

 to the eye, yet close about us and peopled by small living 

 creatures of infinitesimal size, yet of great activity and power. 

 These were the Bacteria and allied organisms. The little 

 people, the fairies, had gone ; but in their place were found 

 creatures of even smaller dimensions. Some of these were 

 beneficent organisms, but others were pathogenic and able to 

 develop poisonous products of a most deadly order ; the toxins 

 of these pathogenic organisms forming a host of dreaded diseases 

 to which a proportion of humanity daily succumbs. And the 

 movements of these bacteria and their allies bear no little resem- 

 blance to, though marking an advance upon, the movements of 

 inorganic and organic matter that are called Brunonian. 



It may be crudely and ignorantly asserted that these 

 Brunonian movements are due to convection currents in the 

 water. A study of them by a high power of the microscope 

 very rapidly disposes of this assertion. And in a publication of 

 the standing of the Micrographic Dictionary — of which book 

 the library of this Society possesses no fewer than three copies — 

 it is asserted that the movements last but a brief time, and the 

 particles soon come to rest against the sides of the chamber in 

 which they are confined. The movements may be said to be only 

 commencing when the convection currents cease. And no one 

 who has watched day by day, as I have done, some of my 

 " preparations," and has seen week by week the particles continue 



