GENERAL PROPERTIES OF BACTERIA. 3! 



and produce new individuals the increase in the total amount 

 of living material implies the production of a considerable 

 quantity of new organic material. The living bodies of the 

 new bacteria are made out of the food upon which the 

 bacteria live, and this involves a chemical synthesis of com- 

 plex out of simpler material. 



2. Analytical Processes. These are processes of decom- 

 position by which complex bodies are reduced to simpler 

 ones. The great majority of bacteria live upon complex 

 chemical foods, and these are broken to pieces to serve 

 them as food and are reduced to simpler compounds. Bac- 

 teria are, indeed, one of nature's chief agents for break- 

 ing complex compounds into simpler ones. Throughout 

 nature bacteria are constantly engaged in this process; in 

 the water, in the soil, in every bit of decayed material, the 

 world over, we find myriads of bacteria actively engaged in 

 producing such chemical destruction. The extreme signifi- 

 cance of these processes for the general life of the world 

 need not be considered here, having been treated of in an- 

 other work. In considering the relation of bacteria to dairy 

 problems we are concerned with both tke synthetic and the 

 analytical processes. In general, however, it is those proc- 

 esses by which complex bodies are reduced to simpler ones 

 that form the larger part of the changes which bacteria 

 produce in milk products, and the synthetic processes con- 

 cern us only slightly. But even of these analytical proc- 

 esses we know very little, and our study of bacteria in milk 

 products tells us as yet little of the actual chemical changes. 

 But the exact chemical nature of these products is a matter 

 of little practical significance to the dairyman. He is inter- 

 ested in the general effect, rather than in the chemical 

 nature of the new products formed by bacteria. We shall 

 not attempt, therefore, to follow out in any detail the chem- 

 ical results of bacteria growth in milk, and we may leave 

 this general subject with this brief outline. 



