384 



EXPERIMENT STATION RECORD. 



condensation is mipable of forming various sugars, or it must by oxida- 

 tion be (japable of being reduced to formic aldeliyde. 



The following table shows the value of a number of compounds as 

 sources of carbon for fungi: 



Coinpotiudx (irailahle as sourven of oarhon. 



The great variety whicli exists in the sources of carbon is also true 

 regarding the sources of nitrogen. Nitrites, in some concentrations, 

 are less favorable than nitrates, and in acid solutions they are poison- 

 ous. Regarding the sources of nitrogen, the author says: 



'■The nitrogen compounds used ninst be converted first into one and the same 

 atomic group before the synthetical work can begin. This group is evidently 

 ammonia, which, in form of salts, is not only very favorable for mold fungi and bac- 

 teria, but also the simplest nitrogen compound that can directly l)e utilized Nitrates 

 have to be reduced first. If organic nitrogen compounds are used as sources of nitro- 

 gen, the latter has to be split off in shape of ammonia before the protein formation 

 can begin. This can be accomplished in many cases by simple splitting; in other 

 cases by oxidation. . . 



"The anaerobic microbes may, by reducing infiuences, transform nitrogen of cer- 

 tain compounds into ammonia, while the aerobic employ oxidation. . , . 



"A very remarlcable case is the assimilation of free nitrogen by certain bacteria of 

 the soil, as was asserted years ago by Berthelot and recently confirmed by Wino- 

 gradsky. The free nitrogen is here probably first converted into ammonium nitrite, 

 and the nitrous acid then als(T rapidly Veduced to nmmonia." 



As sources of sulphur the organic sulphur compounds must be split 

 up, forming hydrogen sulphid, to become available. The hydrogen 

 sulphid is produced only in such (luantity as is immediately required, 

 an accumulation being noxious. 



The conclusion is reached that tiie atomic groups serving for tlie 

 formation of proteins in fungi are formic aldehyde, ammonia, and 

 hydrogen sulphid. Among chloroj^hyll bearing plants carbohydrates 

 are i^roduced by assimilation, and these furnish the principal source of 

 carbon for proteids. Nitrates or ammonia salts supply the nitrogen 

 and the sulphates the sulphur. The reduction of the nitrates and sul- 

 phates must take i)lace, as in the case of the lower fungi. When all 

 conditions are favorable the synthetical processes take i)lace so rapidly 

 that the intermediate steps can not be directly traced. Numerous 



