SOGREL ESSE MESS” 23 ETE gee Prt 3 is see: 
TENGCStp tT et 
WATTERSON: EFFECT OF CHEMICAL IRRITATION 299 
crease :* (1) Although oxalic acid is a normal product of metab- 
olism of the fungus, it is to be regarded nevertheless as a product 
of incomplete oxidation, and if the metabolic activity were in- 
creased, more CO, might be produced and therefore less oxalic 
acid. (2) Thesame result would occur in case the acid should dis- 
appear through a further ‘‘ working-over”’ on the part of the fun- 
gus. Thereby it could be taken up again as building material or 
be decomposed without being useful to the fungus. Yet, as shown 
by Wehmer,} oxalic acid is poor food stuff for Aspergillus, and in 
the presence of a plentiful supply of sugar would probably re- 
main intact. (3) Those materials (carbohydrates, etc.) which in 
normal growth are, by metabolism, transformed in part into oxalic 
acid, in consequence of increase in growth due to the stimulation 
are not separated out in that form, but are changed directly into 
the fungus body, in short, are applied as formative material. 
Of these three possibilities, Ono concludes from his experi- 
ments that the third is the true explanation, since in every case 
the economic coefficient was much greater in the control than in 
the stimulated fungus. “Dieses Verhaltnis deutet also an, das 
die Pilze bei Anvesenheit von Zinksulfat veranlasst wurden, mit 
cinem verhaltnismassig kleinen Verbrauch von Zucker eine bedeu- 
tend gréssere kdérpersubstanz aufbauen zu kénnen.” { This was 
also the conclusion reached previously by Richards. § 
Further support is now given to this explanation by the results 
Presented here, since Ono’s first suggestion is thereby eliminated ; 
that is, the present figures show that an amount of CO, is pro- 
duced by the stimulated fungus which varies a little, being either 
more or less relatively to the weight of the fungus than that pro- 
duced by the normal, but still remains comparatively close to the 
latter. The increase in metabolic activity has, therefore, not in- 
creased (relatively) the production of CO, although the formation 
of oxalic acid under similar conditions was materially checked, 
and the carbohydrates formerly used in the manufacture of the 
latter must consequently be devoted to the building up of new 
Substance in the plant. 
a ee 
* Idem, 157. goo. 
+ Wehmer, Bot. Zeitung, 49: 553. 189I- 
tOno, /. ¢. 160. 1900, ; : 
2 Richards, H. M. The effect of chemical irritation on the economic coefficient of 
Sugar. Bull. Torrey Club. 26: 463-479. 
