MICRO-ORGANISMS AND 

 FERMENTATION. 



CHAPTER I. 

 MICROSCOPICAL AND PHYSIOLOGICAL EXAMINATION. 



1. MICROSCOPICAL PREPARATIONS, STAINING, AND 

 MICRO-CHEMICAL EXAMINATION. 



Microscope will be for all time of paramount aid in 

 the investigation of micro-organisms, since these, as in- 

 dividuals, are almost always invisible to the naked eye. 

 The earliest important observations in the physiology of 

 fermentation we owe to purely microscopical investigations, 

 and it is only within the last few decades that biological 

 and physiological investigations have been undertaken. After 

 a certain probability had arisen that the same species of 

 micro-organism did not always occur in the same form, work 

 was eagerly commenced in different laboratories with so-called 

 " culture experiments" in which attempts were made, by con- 

 ditions of growth artificially brought about, to observe the 

 different phases of development in one and the same spot, in 

 order to determine thus the entire process of development. 

 The idea was correct, but the way in which it was worked 

 out at that time was so faulty that " culture experiments " 

 threatened in consequence to fall into utter disrepute. The 



