6 MICRO-ORGANISMS AND FERMENTATION. 



2. BIOLOGICAL RESEARCH BY MEANS OF THE MICROSCOPE ; 

 MOIST CHAMBERS. 



A true and thorough insight into the nature of the organ- 

 isms of fermentation is not attainable until the method of 

 physiological investigation is resorted to. As stated above, 

 endeavours were made long ago to devise methods of this 

 nature ; the entire neglect of precautions in carrying out the 

 experiments resulted, however, in complete failure, and a re- 

 action then set in, which found expression, e.g., in the work of 

 Reess on the Saecharomycetes (1870), in which he expressly 

 stated that he had taken no precautions to obtain pure 

 cultures, to such a degree had these cultures fallen into 

 discredit. In the course of the following years, however, the 

 matter took a different turn, and it is, perhaps, an almost 

 unique fact in the history of science, that, in so short a time, 

 a new method of investigation not only made its way, but also 

 yielded practical results, both in pathological science and in 

 our own special branch, results which have brought about a 

 revolution in many previously-accepted doctrines. 



The aim of physiological investigations of micro-organisms 

 is to gain an insight into their development and vital functions. 

 The means to be employed in order to attain such an insight 

 is naturally to determine such conditions for their growth and 

 propagation which will make it possible to observe the changes 

 gradually taking place in the organism itself and in the sub- 

 stances influenced by it. When the object aimed at is solely 

 to obtain a knowledge of the various forms which the organ- 

 ism assumes during its development, the conditions are much 

 more easily attained than when a culture on a large scale of 

 individuals originating from one cell of the species is required 

 for the purpose of gaining an insight, through physiological^ 

 chemical, or purely practical experiments with larger quan- 

 tities of these organisms, into the relations between their 

 forms and external influences and into all their biological 

 functions. In the former case all that is required is a culture 



