OLIVE : MONOGRxVPH OF THE ACRASIEAE. 
467 
every available colony of these micro-organisms, numerous qui¬ 
escent myxamoebae will be accumulated, while there will be no 
other myxamoebae visible within a considerable radius, leads one 
to believe that either the bacteria themselves or, more probably, 
the dissolved products of their activity are utilized (pi. 6, fig. 85). 
After vegetating thus for some time, the individuals either crawl 
out of the colony of bacteria and become aggregated, or more often, 
form fructifications within the limits of the colony itself. When 
motile bacteria are especially abundant, myxamoebae are occasion¬ 
ally loosened from their hold on the substratum by the activity of 
the micro-organisms, assume a rounded form and become seemingly 
‘ dead. In other instances, the protoplasm of the myxamoebae 
seems to be attacked by bacteria and destroyed ; Dangeard (’96), 
for example, has described certain endogenous germs which attack 
the amoebae of Sappinia, and I have myself seen appearances in 
the amoebae of this form which resemble conditions similar to those 
which he figures, although I have never seen any destructive action 
take place in the organism. 
Even though these phenomena suggest that bacteria, or more 
probably, the products of bacterial activity are utilized as food by 
all the species of the Acrasieae, long and careful study leads one to 
the same conclusion which de Bary held concerning the Myxo- 
mycetes, namely, that during the vegetative stage, nourishment is 
mainly absorbed in liquid form, and that the ingestion and digestion 
of solid food particles is exceptional. 
Microcyst formation .— Unfavorable conditions may cause the 
myxamoeba to assume a transitory, isolated, encysted state in which 
the protoplasm may slowly dry up and form a more or less evident 
ectoplasmic membrane about itself. To such a temporary resting 
body, Cienkowsky has applied the term microcyst. Slow drying of 
the hanging drop culture causes the individuals to form such rounded 
bodies of protoplasm, which may be induced to reassume the amoe¬ 
boid condition by the addition of more moisture. Fayod describes 
(’83) a peculiar method of microcyst formation in Guttiilina protea.^ 
which takes place in a concentrated nutrient liquid, or when many 
bacteria are present or the culture is otherwise impure. The myx¬ 
amoeba becomes rounded and shows a peripheral vacuole, which, after 
one or two hours, becomes elongated and continues to grow around 
within the peripheral protoplasmic membrane until the inner mass is 
