Jan. 17, 1916 
Plenodomus fuscomaculans 
737 
We have, therefore, in autointoxication a phase of the major factor, 
acid or alkaline reaction, and while definite harmful bodies of a protein 
or amid type are known for organisms and may have been present here, 
we have in the end products of protein and carbohydrate dissimilation 
harmful constituents whose influence may be to limit either growth or 
reproduction. 
Chemical Factors 
QUANTITY or FOOD 
The quantity, rather than the quality, of the food needed for this 
organism can more conveniently be considered at the outset. As was 
stated at the beginning of the experimental work, there is a certain 
minimum for growth and also for reproduction. Naturally, reactions 
taking place at the base level of nutrition are sharper and less obscured 
than those taking place where food is in abundance and the factors of 
reaction, autointoxication, etc., have greater and greater influence. For 
this reason, once the capacity of this organism to grow and reproduce 
upon material almost devoid of nutrients was recognized, many of the 
experiments with other factors have been performed with the food supply 
reduced to a low level. 
This power to grow upon simple stuffs and with them in extremely 
high dilution naturally led to the question of the minimum essential. 
Growth and reproduction in distilled water has already been men¬ 
tioned. The distilled water used in the first experiments was the ordinary 
distilled water of the laboratory. The glassware used was “resistance/' 
cleaned as described. The test tubes were plugged with cotton, and a 
few motes of cotton could be seen upon the surface of the water after 
inoculation. Inoculation was made as described with a spore suspension. 
The number of colonies which resulted from inoculation with similar-sized 
drops of this suspension in Raulin solution was from 5 to 20. These 
details show that a very small amount of organic stuff was introduced 
from the inoculum. After three or four weeks a white or gray filmlike 
mycelium could be seen, either attached to the glass or floating near the 
bottom of the test tube. After a month or, at times, two months 2 to 5 
pycnidia were produced under the water. 
It is difficult to understand where the carbon and nitrogen used by the 
fungus came from. The minerals might be accounted for more or less 
satisfactorily by assuming that they came from the glass, which is 
slightly soluble. For the organic stuffs we have a few possibilities. The 
nitrogen may have come from ammonia in the air, and the carbon from 
the small bits of cotton dropped from the cotton plug. It is more than 
likely that the distilled water carried some oily volatile material, which, 
while not strongly influencing conductivity, gave a suitable foodstuff 
for the fungus. Or we have the possibility, first pointed out by Elfving 
(1890), that organisms may be fed by small quantities of volatile sub- 
