THE FORMATION OF PROTEIDS IN PLANT-CELLS. 



53 



of the tartrate, both kinds of fungi developed well simultaneously. 



It is of interest to compare the amount of mould-fungus 

 with the quantity of the compounds used for development ; con- 

 siderable differences are here observed. While isobutylic alcohol 

 yields only 9 — 10% fungoid matter, asparagin yields nearly 22%; 

 tartaric acid yields less than succinic, tannin less than sugar. 

 Albumin in 1 % solution will yield about 23% of its weight, while 

 a mixture of albumin (1%,) and cane-sugar (2%) nearly 33%. 



To those compounds which cannot be utilised by mould- 

 fungi belong maleic acid, T) citraconic, mesaconic, dibenzylma- 

 lonic and diethylsuccinic acid. Benzyl-succinic, disubstituted 

 glutaric acid and oxyisobutylic acid are very poor sources, while 

 malonic, succinic, monomethylsuccinic and monoethylsuccinic 

 acids are well utilised. 2 ) 



But it is not only in regard to the sources of carbon that a 

 great variety exists ; this holds good also in regard to the sources 

 of nitrogen. Of the great number of the latter compounds we 

 mention as examples: nitrates, ammonium salts, glycocoll, aspa- 

 ragin, kreatin, allantoin, methylamin, acetamid, methylcy- 

 anide, betaln, strychnin. Nitrites are in a certain concentration 

 less favorable than nitrates and are in acid solutions poisonous. 

 Ferrocyanide of potassium is but a poor source of nitrogen while 

 hydroxylamin and diamid cannot be utilised at all, being strong 

 poisons, and azoimid only in high dilutions. 3 ' For the same 

 reasons, as explained above for the sources of carbon, the nitro- 

 gen compounds used must be converted first into the 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 mould-fungi and bacteria, but 

 also the simplest nitrogen compound that can directly be 

 utilised. 4 ' If organic nitrogen compounds are used as sources 



1) E. Buchner B. d. Deutsch. Chem. Ges. 1892 p. 1163. 



2) B. Meyer, Ibid. 1891 p. 1071. 



3) O. Loew, Biol. Centralbl. 10, 588 and Ber. Deutsch. Chem. Ges. Vol. 24, 

 p. 2947. Certain fungi, as Saccharomyccs Mycodcrma prefer ammonia as source of 

 nitrogen to amido-acids and peptone (Bcycrinck). The common beer-yeast however 

 can at low temperature make better use of the latter than of the former, and cannot 

 utilise nitrates (A. Mayer). Laurent has shown that these are converted here into 

 the poisonous nitrites. 



4) Nitrates have to be reduced first. 



