THE GUIDE TO NATURE 
to 
to be linear or quadrangular and that it 
is divided down the middle, showing 
that the diatom is composed of two 
parts, usually alike. You have now dis- 
covered the peculiar structure which 
separates the diatoms from all other 
kinds of plants. Each little cell, no 
matter what its outline or appearance 
may be, is covered by two separate 
shells, composed, more or less, of silex. 
hard and indestructible. Each shell is 
called a valve and the two are united to 
each other by a band on one valve 
which meets and overlaps the band on 
the other exactly as in a candy box. 
You will notice the bands more espe- 
cially on large forms when seen in a 
view at right angles to that of the valve. 
In some diatoms the band is scarcely 
noticeable. Let us now examine sepa- 
rate valves, some of which will appear 
on the slide. If the valve is boat-shaped 
you will see fine or coarse lines radiat- 
ing from the middle line or crossing the 
valve transversely. In the greater num- 
ber you will find that these lines are 
really made up of minute dots which 
are supposed to be pores, in most cases, 
or the lines may be smooth, in which 
case you have under observation a Pin- 
nularia. Suppose, however, you find 
long bands of numerous cells of dia- 
toms placed close together and which 
separate with difficulty. These may 
be Fragilaria or Eunotia. or, if the 
cells are nearly spherical, Meloseira. 
In any case you will find that the box- 
like character prevails in all diatoms 
and that the variations are to a great 
extent in the arrangement of the mark- 
ings of the valves. If the forms are 
circular you will see lines radiating 
from the centre; if linear, elliptical or 
lancet. late, the valve is divided by a 
line into two, sometimes unequal parts, 
or by a dark cleft. Thus, you have 
already divided diatoms into three main 
divisions, one with radiating lines and 
more or less circular outline, another 
with a blank dividing line and a third 
with a true cleft. All diatoms may be 
united under one of these three divi- 
sions. with the exception of certain 
long forms such as Nitzschia. or oval or 
ovate forms, as in Surirella. in which 
you will not see any line or raphe but 
which are known, or supposed, in some 
cases, to have concealed raphes on the 
side. If you once familiarize yourself 
with these differences you will be able 
to arrange nearly all of the diatoms 
found in this locality in their proper 
classes and later they can be divided 
into genera and species, the study of 
which will occupy you for the remain- 
der of your life but it is well worth the 
trouble. 
Two Good Observations. 
Akron, Ohio. 
To the Editor: 
From your interest in the common 
objects of nature, did you ever take 
note of the inside of a cocoanut shell? 
'There you will find the perfect form of 
a leaf with its veins and stem. I re- 
member reading in a book on botany 
that all parts of a plant are formed on 
the plan of a leaf. This is a good ex- 
ample. The three holes or depressions 
are also interesting. One is for the 
emerging sprout, but why the other 
two ? 
When I was in France last year, 
about the most interesting natural ob- 
jects that I saw were the snails. They 
seemed to be everywhere, on the trees, 
bushes and plants. Many of them were 
beautifully marked. We saw large ones 
for sale, sealed shut and about the size 
of a walnut. These were for eating. I 
intended to try some but some of the 
boys said they tasted like paper- 
hanger’s paste, so I didn’t. Then they 
have a pink slug over there, about four 
inches long. These come out early in 
the morning. As they are without a 
shell, I don’t see what protection they 
have from birds. Anyhow the frogs 
eat them. 
Very truly yours, 
Erxest C. Gilbert. 
Pleasure and Money Mad. 
This malady has now become an epi- 
demic among the people of the United 
States. Foolish generation. The 
thoughts of self and a gratification of 
every material desire which will bring 
comfort to the individual is where both 
interest and efforts have been centered 
for months. The ultimate result will 
mean discontent and riot. It takes 
something greater than wealth to bring 
happiness. Only a life which puts self 
last and the other fellow first ; which 
considers service, and an honest day’s 
toil far above any monetary value can 
give a safe poise for any human being. 
— The Southern Fruit Grower. 
