THE FORMATION OF PROTEIDS IN PLANT-CELLS. 



49 



I have observed farther that not only methyl alcohol, but 

 also methylal and methyl sulfuric acid 1 ) may in proper dilution 

 (0,2-0,3%) be used as food by bacteria, i. e. as material for 

 building up protein and protoplasm. The group then used for this 

 purpose must contain only one atom of carbon and cannot be any thing 

 else but form-aldehyde, the same substance that forms by condensation 

 various kinds of sugar. Neither acetic, glycolic, nor amidoacetic 

 acid can be utilised as such, but they may lead by oxidation 

 to one compound which can be utilised, viz. to form-aldehyde, no 

 other unsaturated atomic group could result, suitable for 

 synthesis. This oxidation 2 ) in the cells may be expressed by 

 the following equation in the case of acetic acid : 



CH 3 .COOH + O a =CH jf O + CO,-+H,0 

 If this conclusion; is correct, then we can understand, why 

 substances containing the group CHOH are very favorable for 

 nutriment and why the useful qualities increase with the number 

 of these groups (the polyvalent alcohols, the polyvalent acids). 

 We can understand furthermore, why such substances are 

 capable of nourishing certain bacteria endowed with fermentative 

 properties, even in the absence of air, while compounds without this 

 group can be used as food only in the presence of air, oxidation 

 being then necessary to produce this CHOH-group or the 

 isomeric formic aldehyde. But can that conclusion be admitted 

 if formic aldehyde is a poison ? No doubt this seems an objec- 

 tion of weight, but if we consider how easily the formic aldehyde 

 is changed under condensating influences and how indifferent 

 certain compounds of this aldehyde are, the objection no longer 

 appears so serious ; we must only adopt the view that the formic 

 aldehyde undergoes rapid transformations and that no molecule 

 formed remains unchanged for a second. 3) 



1) In this case an alkaline reaction is necessary for obvious reasons. 



2) Oxidation by respiration has here evidently not only the physical role of 

 yielding energy, but also a direct chemical function in preparing the suitable group 

 for synthesis. 



3) Compare U. Loew, Ber. d. Deutsch. Chem. Ges. 22, 484. Synthetical 

 processes require substances of a certain lability; very reactive substances however 

 are more or less poisonous. The objection of some botanists to the view of the 

 formation of sugar from form-aldehyde in plants is not more tenable since Bokomy 

 has shown that the combination of form-aldehyde with primary sodium sulfite can 

 be utilised by plants for the production of starch. Landw. Jahrb. 1892. 



