92 BOTANICAL GAZETTE [FEBRUARY 
of chemical reactions forbid us to believe that such dissociation does 
not go on slightly at low temperatures, even when unaided. But it 
is so slow as to be ordinarily beyond our measurement. The enzymes 
seem to be mere accelerators of the several processes, perhaps pre- 
paring “compatible systems,” as high temperature may do in com- 
bustion; perhaps entering into union with the substance they a 
on and forming compounds which are dissociable at ordinary tem- 
peratures in appreciable amounts. 
The clue to an understanding of respiration has been found, 
ologists at least will do well to drop “combustion” altogether from — 
their vocabulary, as neither the past conception of it nor its probab 
use in the future conduces to clearness of thought. 
NATURE OF ANAEROBIC RESPIRATION. 
The third line of advance has been in a study of the relations of — 
fermentation and anaerobic respiration. The first step was that 
long-sought discovery by BUCHNER, that the process of fermentation 
certain hexose sugars into carbon dioxid and alcohol. But a further 
step in advance has lately been taken. It appears from the work of 
BUCHNER an NHEIMER’® that the alcoholic fermentation is not 
direct, but that it occurs always in indirect fashion, as shown below: 
0 aes 
| | | 
CHOH sa a CHOH H CH,OH 
| 
CHOH = nee E CH, CH; 
CHOH OH OH COOH OH co, 
i 
CHOH CHOn CHOH H CH,OH 
| | 
CH,OH H CH, CH, CH, 
glucose water hypothetical 2 _— nor aay carbon dioxid 
: substance ethyl alcohol 
10 Die eieatoche Vorginge bei alcoholischen ST Ber. Deutsch. 
ere 1 
