1 86 BUTYRIC ACID FERMENTATION. 



tised in 1858 by M. TRAUBE (I.) in his researches on ferments, 

 and A. SPINA (I.) was the first to employ the sodium salt as a 

 reagent for the same purpose. 



115. Clostridium Butyrieum (Prazmowski) and 

 Bacillus Butyrieus (Hueppe). 



Pasteur's discovery that organic life is possible without free 

 oxygen, and that certain organisms can obtain the energy they 

 need by so breaking down organic compounds as to liberate heat, 

 is one of the highest importance for physiology generally. The 

 amount of heat so evolved is naturally much less than it would 

 be if the compounds in question were directly converted into 

 carbon dioxide. Pasteur, however, went somewhat too far in 

 founding on this newly-discovered fact a theory of fermentation 

 which culminated in the assertion that : " Fermentation is a 

 universal phenomenon, and consists of life without air, life with- 

 out free oxygen," because, if this definition be accepted, we should 

 be able to speak of but few phenomena as fermentation, and, in 

 particular, it would be necessary to discontinue the application of 

 the term to those decomposition processes that from time im- 

 memorial have been, and are even now, principally borne in mind 

 in speaking of "fermentation," viz., the alcoholic fermentation 

 excited by yeast, an operation which proceeds both with and 

 without free oxygen. 



To return to the "vibrion butyrique." In the years 1877 to 

 1880, A. PRAZMOWSKI (I.) published a careful morphological in- 

 vestigation of a butyric acid bacterium, presumably identical with 

 the vibrion butyrique though this cannot be stated with certainty. 

 Elevating the designation Clostridium (first used by Trecul, and 

 then only to indicate a form of growth) to a generic term, Praz- 

 mowski named two new species of bacteria Clostridium butyricum 

 and Clostridium Polymyxa. The latter completely coincides with 

 the former both in morphology and life history, but differs from 

 the strictly anaerobic Cl. butyricum both by its inability to exist 

 in the absence of oxygen, and also by its incapacity to incite fer- 

 mentation (in the restricted sense of the term). Fig. 49 reproduces 

 the vegetative forms of growth depicted by Prazmowski as those 

 of his butyric acid bacterium. They are mostly plump rods, some 

 i p broad. The generation period was determined by Prazmowski 

 as about thirty to thirty-five minutes at 35 C., and forty-five to 

 fifty minutes at 30 C. Under certain conditions, and especially 

 whilst young, the rods store up in their plasma a substance which 

 resembles starch (amylum) in being stained blue by iodine. This 

 phenomenon had already been noticed by Tre"cul, who gave it ex- 

 pression in the generic name of Amylobacter, which he applied to 

 these Schizomycetes. During the formation of spores the rods 

 swell up, as related and shown in 49. The power of withstand- 



