762 
Journal of Agricultural Research 
Vol. V, No. 16 
tion of the mycelium, and this we have seen is a resultant of the envi¬ 
ronmental factors. In other words, we must consider in what way a mass 
of mycelium with checked vegetative growth is influenced to reproduc¬ 
tion, while one in active growth is unaffected. 
The cause of this relation to light, or, better, to oxidation, is under¬ 
stood if we take into account the fact that among organisms and among 
parts of the same organism there exists a strong competition for oxygen. 
In the cell itself the various processes inhibit and influence each other 
by their oxygen relations. Oxidation is never at its maximum in the 
cell under ordinary conditions, as simple tests with increased oxygen 
tensions show (Porodko, 1904). Organisms well aerated grow better 
than those in an air supply below the optimum. The action of oxidation 
is to release energy. The materials oxidized are either the foodstuffs 
suitable for nutrition or the cell material which growth has stored up. 
Euler (1909) contrasts growth, a stretching process, with reproduction, 
a differentiating and formative process. Growth is a process which is 
gradual, and it takes place even if only a small amount of energy be 
available. It is a process taking less energy than reproduction, as all 
respiration experiments have shown. The great consumption of energy 
in reproduction is doubtless associated with the great amount of nuclear 
protoplasm which must be formed. Growth, therefore, is the process 
first inaugurated, and the one which continues so long as the food supply 
is abundant and outer conditions permit. It is a static condition, as 
reproduction is dynamic. 
In the hunger state the oxidations are different to a marked degree, 
as Kosinski (1901) has discovered, and here we have the cell reserve 
gradually drawn upon. The fats and even the proteins may be oxidized, 
according to Purievich (1900). But in this hunger state the respiration 
is reduced, according to Kosinski; hence, the working is slow. These 
metabolic relations, in spite of their great complexity, balance each other. 
It would seem that reproduction is not possible under conditions 
favoring growth, because the oxygen supply is all used in ordinary 
metabolism. With the hunger state, respiration is reduced. Oxidation 
becomes vigorous if it be stimulated by light. No doubt any catalytic 
agent would be similarly effective. Once in this hunger state, oxidation, 
if augmented, takes place upon the rich cell stuffs, with the liberation of 
much energy. This energy is used in reshaping the reserve stuffs into 
complex protein bodies—the spores. The sharper the hunger condition 
is made, the more striking the reaction in pycnidium production. The 
sudden withdrawal of the food supply by the transfer of richly-growing 
mycelium to lower concentrations or to distilled water, checks ordinary 
assimilation, with its attendant use of oxygen. If oxidation of the cell 
reserves be inaugurated by light or some strong oxidizing agent, fructifi¬ 
cation takes place. 
