64 INFUSORIA. PAKT in. 



of the elements of inert matter. That question has 

 been decided by direct experiment, for Professor Schultz 

 kept boiled infusions of animal and vegetable matter 

 for weeks in air which had passed through a red-hot 

 tube, and no animalcules were formed, but they appeared 

 in a few hours when the same infusions were freely ex- 

 posed to the atmosphere, which shows clearly that the 

 germs of the lowest grade of animal life float in the air, 

 waiting as spores do, till they find a nidus fit for their 

 development. 



M. Pasteur, Director of the Normal School in Paris, in 

 a series of lectures published in the c Comptes Rendus,' 

 has not only proved that the atmosphere abounds in 

 the spores of cryptogamic fungi and moulds, but with 

 infusoria of the form of globular monads, the Bacteria, 

 and vibrios, which are like little rods round at their 

 extremities and extremely active. The Bacteria mona 

 and especially the Bacteria terma, are exceedingly 

 numerous. These minute beings are the principal 

 agents in the decomposition of organic matter. They 

 are more numerous in dry than in wet weather, in 

 towns than in the country, on plains than on mountains. 



In a memoir read at the Academy of Sciences, Paris, 

 Mr. J. Samuel son mentions that he had received rags 

 from Alexandria, Japan, Melbourne, Tunis, Trieste and 

 Peru. He sifted dust from the rags from each of these 

 localities respectively through fine muslin into vases of 

 distilled water. Life was most abundant in the vases 

 containing dust from Egypt, Japan, Melbourne, and 

 Trieste. The development of the different forms was 

 very rapid, and consisted of protophytes, Ehizopods and 

 true Infusorise. In most of the vases monads and vibrios 

 appeared first, and from these Mr. Samuelson traced a 

 change first into one then into another species of infu- 

 soria. In the dust from Japan he followed the develop- 

 ment of a monad into what appeared to be a minute 



