THE VITAL PHENOMENA OF BACTERIA. 137 



in part also, according to Kriiger and V. 

 Klecki, upon the production of acid from the 

 milk-sugar. The first sort of decomposition 

 can be avoided by careful exclusion of the 

 butter from light and air, the latter by heat- 

 ing or addition of salt. The " rancidity " first 

 mentioned was formerly confounded with real 

 " acidity." 



According to Haenlein, 1 we have reason to 

 hope that the tanning industry also will derive 

 practical benefit from bacteriology. 



The steeping of flax-stems in water as prep- 

 aration for retting is performed for the pur- 

 pose of bringing about a process of bacterial 

 decomposition, and accurate study of this pro- 

 cess will perhaps enable us to isolate bacterial 

 species specially fit for this purpose and to use 

 them in pure cultures. 



In all these cases in which pure cultures of 

 bacteria are employed for reaching a desired 

 specific effect, it is always our aim to obtain a 

 definite species of bacterium and to utilize the 

 constancy of this species to generate definite 

 products ; whence we might infer that the 

 constancy with which a species produces pig- 

 ment or fermentation or disease is absolute, 

 and that the effect is wholly contingent upon 

 the kind of bacterium present. 



i Centralbl. f. Bakt., Abth. II., I., p. 26. 



