AMCEBA 
143 
peculiar taste may be due either to animals or plants, or to 
both. When it is due to animals, it is caused by a dis¬ 
agreeable oil formed by a certain kind of Protozoa. 
By far the greater number of Protozoa are harmless, 
and many are helpful to us in that they serve as food for 
fishes. Others, however, may become parasitic in our bodies, 
and thus cause such diseases as malaria, yellow fever, or 
sleeping sickness. 
112. Amoeba. 1 — The name Amoeba (a-me'ba) is given to 
several different Protozoa, but all represent the simplest 
form of animal life known 
to us. For this reason 
they are always studied in 
biology. In order to de¬ 
scribe correctly the struc¬ 
ture of even so simple an 
animal as the amoeba a few 
new words are necessary. 
Structure of Amoeba. — It is difficult for inexperienced 
students to see the living amoeba through the microscope, 
because the whole cell has a faint, grayish appearance, 
and in a strong light is transparent. But if this grayish 
appearance of protoplasm is once seen, it is always re¬ 
membered. 
There is no well-defined cell wall; therefore the amoeba 
1 No suggestion can be made which will always enable the teacher to 
secure amoebae. They are more frequently found in the slime and mud of 
stagnant water than anywhere else. Paramecia and other infusoria can 
usually be secured in abundance by placing a handful of hay or leaves in a 
jar and covering them with the ordinary water used in the laboratory. This 
is called a protozoan culture, and should be started about four weeks before 
the material is wanted for class study. The length of time that the culture 
should stand can be lessened by adding a little beef-extract and by keeping 
the jar near a radiator. Water sufficient to keep the hay or leaves covered 
must be added from time to time. When a good culture of Paramecia is 
once secured, the jar should be kept from year to year, simply adding water 
to the dried hay left in the jar when Protozoa are desired. 
Figure 133 . — Diagram of an Amceba. 
