354 
Journal of Agricultural Research 
Vol. XXIV, Noi 4 
A temperature of between 19® and 22° C. was used for practically 
all the work reported in this paper. Incidentally it was found that 
cultures kept in the refrigerator at 10® showed an unusually good spore 
condition. It was very likely due to the fact that so low a temperature 
inhibited the growth and was about the optimum temperature for preser¬ 
vation of spores after their formation. Cultures kept in' the refrigerator 
were always kept at room temperature for about a week after they were 
inoculated. 
During the later spring months the light incubator in the greenhouse 
warmed up in the middle of the day to 30® or 35® C. We found that cul¬ 
tures kept in this incubator during that time deteriorated quickly. 
The conclusion drawn from our own experience and that of others 
was that cultures can be grown as well at room temperature as at a 
fixed temperatme, provided the temperature does not go lower than 12® 
or higher than 25® C. In case it is desirable to keep spores in a normal 
condition for a longer period of time than is possible at room tempera¬ 
ture this can be done by keeping them in a refrigerator at 10® or less. 
EFFECT OF AOn 
Careful study of the series of cultures grown for the purpose of noting 
the effect of age on spore formation was in some measure disappointing. 
Isolated examples could be found that would illustrate practically any 
theory one might wish to propound. Too many factors enter in, such 
as moisture, nutrients, temperature, etc., for one to be able to make 
definite conclusions as to the effect of age. It seems that if all conditions 
are right to produce a “hoch’' ^ stage of a normal culture, age does not 
enter in more than that a very young culture or a very old one can not 
produce a “Hochkulture.” Only relative age then, would seem to be 
of importance. 
CONCLUSIONS AND SUGGESTIONS ON METHODS 
The effects of media, temperature, light, and age, though not always 
very great on cultural and spore characters, are sufficient to make it 
advisable in describing characters to describe the culture media and 
conditions so freely as to make the repetition of the culture upon the 
same medium and under approximately the same conditions easily 
possible, to note under what conditions these results were observed, 
and to keep them within certain limits. 
Our experience would suggest that cultures grown on a hard oat agar, 
in diffuse light, and at room temperature will give the best satisfaction. 
* Appel and Wollenweber ( 2 ) in their attempt to find distinctive terms by which to designate the degree 
of devdopment and the age of the cultures created six terms which are briefly defined as follows: 
Ankulturb: a little mycelium from the original substance of some Fusaria is inoculated on tubers or 
stems. A pure, rich mycelial culture results in which there are either no conidia or only a very few, and 
these are apt to be irregular in shape and septation and are not suitable for morphological research. 
Normkt7i,turr: A culture which produces conidia readily and in which the spores are regular in form 
and septation. 
Abkui,tijrr: A ctdture in which deterioration has set in, and the spores which have not disintegrated 
are small and usually have fewer septations than do those in the Normculture. The Normkulture is sub¬ 
divided into three stages: 
The Junokui,turr, usually less than 8 days old, is one in whidi the spores have not reached a constant 
form of development, and spores of varying sizes and septations are found. 
In the Hochk:ui,turr the spores are truly normal, that is, comparatively even in size, shape, and septa¬ 
tions. 
In the Ai,tkui,turb the spores, due to lack of moisture or food, shrink a little in size; or if new spores 
are formed they are undersized, yet not deteriorated enough in form to belong to the Abkulture. 
Plate I. C and D, illustrate the “alt” and “hoch” stage of the Normkulture as seen in our work. 
