1 6 LIFE AND HER CHILDREN. 
stretched threads, a living animal (see tf,Fig. i), floating 
in search of food. Examine it how we will, we can 
find in it no mouth, no stomach, no muscles, no 
nerves, no parts of any kind. It looks merely like 
Fig. i. 
The Thread-slime.* Haeckel. 
a, In its natural round shape, immensely magnified ; b, spreading itself 
over a small animal, c (Ceratium), to suck the soft body out of the shell. 
a minute drop of gum with fine grains in it, floating 
in the water, sometimes with its fine threads out- 
stretched, sometimes as a mere drop ; and if we take 
it out and analyse the matter of which it is made, 
we find that is much the same as a speck of white- 
of-egg. Is it possible that it can be alive ? How can 
we be sure ? In the first place it breathes. If it be 
kept in a drop of water, it uses up the oxygen in 
it, and makes the water bad, by breathing into it 
carbonic acid ; then it moves, and, as we shall see 
presently, can draw in and throw out its fine threads 
when and where it chooses ; again it eats, feeding on 
the minute jelly -plants in the water, or even on 
* Protogenes. 
