OLIVE: MONOGRAPH OF THE ACRASIEAE. 
465 
Bary’s conclusion is justifiable, however, from their researches, 
that, in the vegetative stage of the Mj^omycetes, food for the 
most part is appropriated in solution, and only occasionally are 
solid bodies utilized. 
In the case of the Acrasieae, the investigators who have studied 
these organisms have come to various conclusions concerning their 
method of taking food. Brefeld in his earlier paper (’69), says 
that the myxamoebae of Dictyostelium are able to take solid bodies 
into their interior, but he was unable to settle the question as to 
whether the ingested particles were in any Avay utilized. Later 
(’84), he asserts that solid bodies never penetrate into the interior 
of the myxamoebae of Polysphondylium or Dictyostelium, and that 
the latter grow exclusively through the absorption of dissolved 
nourishment. On the other hand, van Tieghem (’80), thought that 
there was probably a digestion of the bacteria which were engulfed 
by the myxamoebae of Acrasis. Fayod (’83), found that in the 
amoeboid condition of Guttulina protea, carmine particles, bacteria, 
etc., were ingested and assimilable portions retained, while the 
undigested portion was thrown out at the posterior end of the myx- 
amoeba, remaining fastened to it for some time. 
I have made repeated observations on the vegetative stages of 
various species of Acrasieae in order to discover the source of their 
food, and have found that pure cultures may be grown to maturity 
inTa hanging drop of nutrient decoction without the ingestion of 
anj^Jsolid particles. It is true, however, that such cultures, when 
absolutely pure, do not develop luxuriantly, for the fructifications 
are fewer in number and smaller than usual. Cultures free from 
bacteria, furthermore, are exceedingly difficult to obtain, since 
individuals or spores of these organisms are carried up by the 
ascending colony of myxamoebae, and a careful transfer to a ster¬ 
ilized culture medium rarely fails to show within a short time the 
presence of various species of bacteria. If a complete fructifica¬ 
tion of Dictyostelium or of Polysphondylium is transferred, colonies 
of bacteria frequently develop at points along the stalk, and also 
among the spores of the head, thus indicating the presence of these 
organisms in the mucus which surrounds the stalk as well as in that 
of the sorus. 
In their natural saprophytic environment, the myxamoebae cer¬ 
tainly encounter numberless bacteria during their wanderings. In 
