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 g — 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 maleïc acid, 1 ) 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, betaïn, 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. Chern. Ges. 1892 p. 1163. 
2) B. Meyer , Ibid. 1891 p. 1071. 
3) O. Loew, Biol. Centralbl. 10, 588 and Bei*. Deutsch. Chem. Ges. Vol. 24, 
p. 2947. Certain fungi, as Saccharomyces Mycodcrma prefer ammonia as source of 
nitrogen to amido-acids and peptone ( Beyerinck ). 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. 
