GENERAL FUNCTIONS OF MICROBES 5 



Grindelwald, which is composed of a calcareous schist, black, 

 friable, and crumbling down. There is therefore a sort of 

 putrefaction of rocks (alkalis and alkaline earths). According 

 to Fausto Sestini the carbonic acid produced in the respira- 

 tion of plant roots hastens the breaking down of feldspars. 



Mosses, lichens, algae and bacteria prepare the way for the 

 highest plants. The more there is growth of plants, the more 

 there is decomposition. In this way, soil or humus has little 

 by little spread over all the earth. 



II. — Fermentation of Carbohydrates. 



These fermentations restore to circulation the hydrocarbons 

 of animals and plants. 



For the decomposition of sugars, starches, fats, glucosides, 

 and celluloses, several series of fermentations are necessary, 

 each 'Supplementing another in the work. The anaerobic 

 organisms break down the large organic molecules, whereas 

 the aerobes carry out, in particular, oxidations. When the 

 bacteria are insufficient, the moulds continue the work. 

 Finally, nothing is left but carbonic acid and water. All the 

 operations which in our laboratory analyses we distinguish and 

 conceive in terms of abstract formulae, are combined and 

 intermingled in nature, each succeeding and limiting the other. 

 The yeasts transform sugars into carbonic acid and alcohol. 

 Alcohol attacked by the acetic ferments is turned into acetic 

 acid. Finally, the Bacterium aceti can split the acetic acid 

 of vinegar into carbonic acid and water. The Mycoderma mm 

 destroys and oxidises both alcohol and acetic acid, producing 

 again carbonic acid and water. The sugar contained in 

 Raulin's fluid (zi. infra), for example, is attacked by Aspergillus 

 niger, the products including oxalic acid. Various moulds and 

 bacteria turn starch into sugar; it is the moulds in particular 

 which complete the oxidations, producing carbonic acid and 

 water. 



Milk left to itself ferments, i.e., produces lactic acid, which, 

 meeting with an alkaline carbonate, furnishes calcium lactate. 



