RHIZOPODA—AMCGBINA, 77 
It would be difficult to say exactly what is the form these creatures 
assume. They frequently have the appearance of small, rounded 
masses, like drops of water; but, whatever their form may be, it is 
often so unstable, that it changes, so to speak, every moment. 
This instability is one characteristic manifestation of life in the 
Amebe, which are naked beings, without any apparent organisation ; 
in fact, they may be said to occupy the first step in the scale of 
creation. 
If we examine one, at first it looks like a transparent immovable 
drop. We then see it putting forth a pseudopod, which, gliding like 
a streak of oil under the thin covering glass, as we view it through a 
microscope, begins by fixing itself to some point, afterwards slowly 
attracting to itself the whole of its body mass, and thus gradually 
increasing its bulk under the observer's eye. 
The Amada, according to their dimensions and degree of develop- 
ment and activity, successively emit a greater or smaller number of 
pseudopods, none of which are precisely alike, but after having 
appeared for a short time, each successively will be seen to re-enter 
the common mass, with which it becomes completely incorporated. 
Variable in their respective forms, these pseudopods present ap- 
pearances quite different in the several genera. They are more or 
less attenuated, and often branching ; sometimes they spring in all 
directions from the animal mass. 
If we ask how these animals are nourished in which no digestive 
apparatus can be distinguished, the question is difficult to answer. 
It was once thought that they are nourished by simple absorption, 
and by absorption only. In the interior of the gelatinous mass which 
constitutes these animals, however, microscopic alge are frequently 
discovered. Indeed, some of them are very voracious feeders, and 
may be seen completely stuffed with diatoms, or pretty green desmids. 
“ We can conceive,” says Dujardin, “ how these objects have pene- 
trated to the interior, if we remark that in creeping on the surface of 
the glass, to which they adhere very exactly, the Amebe, can be 
made to receive by pressure foreign substances into their own bodies 
by means of the alternate contraction and extension of the various. 
parts natural to them. ; 
The Amebe are often observed to be tinted red or green; this 
apparently arises from a special colouring matter which has been 
absorbed into their body substance, and the brightness of their colour 
is in direct proportion to their state of health. 
The question arises, How do these creatures, so simple in their 
organisation, propagate their species? 
