70 PLANT PHYSIOLOGY 



In general it is assumed that there is no great difference betv/een the taking 

 up of oxygen from oxides to effect combustion of sugar and to bring about a 

 decomposition of sugar into alcohol and carbon-dioxide, or into butyric acid, 

 hydrogen, and carbon-dioxide. Following PASTEUR, one may look upon these 

 splittings as a transference of oxygen from one carbon atom to another in the 

 same molecule. From that point of view, respiration and fermentation are to 

 be considered always as cases of oxidation. While, however, in the so-called 

 oxidizing fermentations, where different organic acids are formed, the fer- 

 mentations go on without free oxygen, in normal respiration free oxygen is 

 essential. 



We must now strictly limit ourselves in any further enumeration of fer- 

 mentation phenomena. Our most important work is to find out how the 

 products of the animal and plant worlds are transformed into simple bodies by 

 the fermentative agency of lower organisms, so that these may again become 

 available for the nutrition of higher plants. (For all details see LAFAR'S 

 Mykologie.) 



216, 1. 51, after organisms, read At least the special capacity of these 

 Bacteria is in accord with enzymic action (BucHNER and MEISENHEIMER, 1903). 



217, 11. 25-53, f or Butyric acid . . . cellulose, e. g. the read Among the 

 fatty acids which arise from sugar through the activity of fermentative 

 organisms we have, in speaking of Clostridium pasteurianum, already mentioned 

 acetic and butyric acid. We should note, though quite briefly, that in addition 

 formic acid and also higher fatty acids, such as propionic and palmitic acids, 

 make their appearance in the so-called butyric acid fermentation. Probably 

 we might increase the number of these acids considerably if more care 

 were taken in looking for them. Further, it is of interest to note that there 

 are also animal anaerobes, e. g. intestinal worms belonging to the genus Ascaris, 

 which, according to WEINLAND (1901), induce propionic acid fermentation. 



It was also noted above that many butyric acid formers are not restricted 

 to sugar, but make use as well of polysaccharides, such as starch and cellulose. 

 Since cellulose is one of the chief down-grade products of plant metabolism, its 

 further utilization by micro-organisms is of the greatest interest. Among the 

 forms which carry out this work is a 



218, 11. 14-16, for become transformed . . . support of life, read in the 

 form of humus, turf, and coal, become once more available for the support of life. 



1. 19, for In a word read Recently, 



1. 36, after OMELIANSKI read 1902, 



1. 47, for [OMELIANSKI, 1904 b] read (Comp. LAFAR'S Mykologie, III. 269.) 



1. 48 P. 219, 1. 36, for On studying . . . proteid fermentation read 

 Just as the alcohol which arises in alcoholic fermentation is further worked up 

 by other organisms, so the products of other fermentation processes are em- 

 ployed by yet other organisms still. We shall speak of the employment of 

 greatly reduced bodies like H 2 S, NH 3 , H, and CH 4 in the next lecture. How 

 butyric acid is broken down does not appear to have been investigated ; but 

 OMELIANSKI (1904) has made us acquainted with the anaerobic decomposition 

 of formic acid. Calcium formate undergoes the following transformation : 



Ca(CHO 2 ) 2 + H 2 O = CaC0 3 + CO 2 + 2H 2 



The organism which brings aboutt his fermentation, viz. Bacterium formicicum, 

 is able to make use of the simplest imaginable organic compounds, but it can 

 use peptone as well. On the other hand, it can make no use of the closely 

 allied fatty acids, although it can employ a whole series of sugars and sugar- 

 alcohols. In OMELIANSKI'S cultures, in addition to CO 2 and H, there were 



