It stood out sharply when he focused—the white, jellyfish shape of a single-celled leucocyte.
There are many kinds of these single-celled plants in the world.
There still exist large numbers of similar “single-celled organisms.”
They are single-celled organisms and each individual has the prime factors of life, assimilation, growth and reproduction.
A single-celled, protoplasmic organism, which is constantly changing its form by protrusions and withdrawals of its substance.
Now the single-celled Infusorian is in many respects comparable with the single-celled germ of the higher animals.