Harriet Randolph.

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somites. Their short ducts open to
the outside in the constrictions be-
tween the 9th and 10th and the 10th
and 11 th somites, respectively.

(/*) The ovaries: two pear-shaped bodies at-
tached to the anterior wall of the 13th
somite, one on each side of the median

(g) The oviducts: two short, funnel-shaped
tubes passing through the dissepiment
between the 13th and 14th somites, one
on each side of the median line. They
appear often as thickenings of the dis-
Make an enlarged diagram of the reproductive

7. The nervous system.

Central nervous system. Observe:


(a) On the dorsal side of the pharynx in the
2d or 3d somite a pair of pyriform
white bodies united in the median line :
the cerebral ganglia.

(b) From each lobe a nerve-cord, the circum-

cesophageal commissure, passes down at
the side of the pharynx, in the con-
striction between the bnccal sac and
the pharynx, to the suboasophageal gan-
glion (first ventral ganglion) on the lower

(c) From the suboesophageal ganglion a long

double ventral nerve-cord passes poste-
riorly in the mid ventral line.
Peripheral Nervous System.

(d) Two large nerves which run anteriorly

from the cerebral ganglia.

(e) A nerve from each half of the circum-

03sophageal commissure near the union
of the two halves on the ventral side.
(/) Typically three pairs of nerves in each
somite : two pairs arising from the gan-
glion and one pair (septal nerves) from
the cord immediately behind the dis-
Make a diagram (X 6) of the nervous system.

(At this point the buccal sac, C. II. 5. (a), may

be looked for.)


8. The cuticle.

With forceps strip off under water the cuticle from
the lateral and ventral aspects. Mount it in
ivater on a slide, and examine first ivith a low
and then ivith a high power.

With the low power observe :

(a) The tubular processes of the cuticle torn

from the setae-sacs.
With the high power observe :

(b) The thin transparent membrane not com-

posed of cells. It is traversed by deli-
cate lines and perforated by minute

9. Before leaving the anatomy of the earth-

worm see a demonstration of a nephridium
from a recently chloroformed worm.
10. Make a drawing ( X 5) of an egg-capsule.

I. Prepared transverse section.

For detailed directions see "General Bi-
ology," Sedgwick and Wilson, second edition,
1895, pages 91 to 95 inclusive.
Make a diagram shotving in outline the different

regions of the section.
Sketch accurately, much enlarged, a portion of the

section a few cells in ividth.

Make an accurate sketch of the cross-section of the
ventral nerve-cord.


II. Prepared longitudinal sections to show the re-
lations of cerebral ganglia, alimentary canal,
circumoesophageal commissure, and ventral

1. Section through the median region (cerebral

ganglia, alimentary canal, ventral nerve-

2. Section at one side of the middle region

(circumoesophageal commissure).
Diagrams in outline !


Mount some of the water or sediment containing
amoebae under a large cover-glass. /Search for
them with the low poiver, and when found study
tvith the high poiver. Observe :

I. General Characters.

1. Form : in the motile state characterized
by irregularity and continual change ;
rounded processes (pseudopodia) formed by
the protrusion and the retraction of the

II. Structure.

1. An outer transparent layer : the ectoplasm.

2. An inner more granular layer : the entoplasm.

3. A spherical or disk-shaped body in the ento-

plasm : the nucleus.

4. A spherical space filled with fluid, disappear-

ing and reappearing at intervals ; the
contractile vacuole, often situated in the
hinder part of the body. If the pulsations
can be readily observed, describe them.

5. Water-vacuoles (not always present) : in the


6. Food masses in food-vacuoles in the ento-

Sketch an amoeba ( X 8 or X 10).

AM(EBA. 25

III. Movements. Observe:

1. The mode of formation of a pseudopodium.

2. The process of locomotion.

3. If possible, the taking in of food and the

passing out of waste matter.
Make a series of outline sketches at regular intervals
to show the changes of form.

4. The effect of higher temperatures on the

movements of an amoeba. (Heat gradually
on a warm stage* Record the result.)

IV. [Reproduction.

If an amoeba be found dividing by fission, ob-
serve and sketch it.
Y. Chemical and Mechanical Tests.

1. Treat with magenta or iodine. Record the


2. Crush a stained specimen. Describe the result.

* A simple warm stage may be made of sheet copper the width
of a glass slide and several times its length, with a hole pierced
an inch and a half from one end to correspond to the aperture of
the diaphragm. To use the stage, place it on the stand of the mi-
croscope and fasten the slide down upon it with the microscope-
clips. To heat the copper, place a lighted alcohol-lamp under the
free end. A simple method of determining when the temperature
of the slide has reached approximately 38 degrees is to place upon
it a small fragment of paraffine that has been mixed with suffi-
cient benzole to reduce its melting-point to the desired degree.


A. Mount under a cover -glass supported by a piece of

hair or a bristle a drop of blood obtained by prick-
ing the finger near the root of the nail with a fine
needle. Surround the margin of the cover-glass
with vaseline. Make the preparation as quickly
as possible in order that it may not dry.
Disregard the colored corpuscles and look for the
less frequent white ones. Observe :

I. General Characters.

1. Form : irregularly rounded ; changes occur
as in amoeba, but more slowly.

II. Structure.

1. Granular protoplasm.

2. Nucleus (rarely visible in the fresh state).

III. Movements.

Place the preparation on a loarm stage and heat
gradually to 38 degrees C. Record the result.

B. Mount in the same way corpuscles of the codomic

fluid of the earthworm. This may be obtained
by exposing the worm for a moment to the
vapor of chloroform, when the fluid will exude
through the dorsal pores j touch a cover-glass to
the fluid and instantly mount.

Note the shape, and changes of form that may




Mount on a slide some sediment containing hcema-
tococcus that has been soaked for a feiv hours
in water. Cover and examine with a low power.
Find :

I. External Characters.

1. Red or green spherical cells.
With a high power observe :

2. Size. (Measure.)

3. Form.

4. Color : red, green, or in some cells both red

and green.

II. Structure.

1. Colorless cell-wall.

2. Cell-contents: more or less granular; con-

sisting of protoplasm, a centrally situated
nucleus and superficial chromatophores in
which the coloring matter is deposited.
(The outlines of the chromatophores are
difficult to distinguish in the living state.
The nucleus is more easily seen in the

* Haematococcus can sometimes- be found in old marble urns.
When once obtained the same supply will last for a number of
years. It should be wet each year with spring-water, and is be-
lieved to flourish better if a little powdered marble is added.



smaller, green form, Pleurococcus. See
Sketch (X 6).

3. Look for cells whose contents are undergoing

endogenous division. Sketch.

4. Treat with iodine. What structures show

more clearly?

5. Crush the cells by pressure on the cover-glass.

Note the unstained cell-walls, and the cell-
contents stained brownish yellow with iodine
(showing the presence of protoplasm).
B. MOTILE STAGE : Zoospores.

(These develop from forms in the resting stage
that have been in water for a number of hours.)
Study tvith a high power. Observe :
I. Larger motile forms : macrozoospores.

1. Form : pear-shaped.

2. Color.

3. Structure.

(a) Thin colorless cell-wall.

(b) Central protoplasmic mass separated from

cell-wall by clear space. Through the
clear space delicate protoplasmic threads
extend from the central mass to the
inner surface of the cell-wall (probably
to a thin layer of protoplasm lining
the cell-wall).

From the colorless apex of the proto-
plasm two processes pass to the pointed


end of the cell-wall. They are con-
tinued beyond it as rapidly vibrating

(c) Nucleus (not visible in living specimen).

(d) Chromatophores.

4. Movements. Note :

(a) Active locomotion.

(b) The rotation of an individual on its own


(c) The movements of the flagella. (Try to

find a specimen whose movements have
become so slow that the flagella may be

5. Stain with iodine. Look for the flagella.
Sketch (X 6).

II. Smaller motile forms : microzoospores. Like the
macrozoospores except in regard to size and
cell-wall, etc.
Sketch (X 6).


Soak in water for a few hours pieces of bark, etc.,
that have a green powdery coating or discolora-
tion. Remove some of the green layer with the
point of a scalpel, mount in ivater, and study
ivith a high power. Look for :

1. Nucleus.

2. Individuals multiplying by cell-division.


Mount a small drop of ivater containing Para-
mcecia under a supported cover-glass. Examine
first with AA%, and observe where they are most
quiet ; then study with D 2.

I. General Characters.

1. Form : elongated, flattened, slipper-shaped ;

the anterior end rounded, the posterior

2. Movements : by means of cilia over the entire


3. On the ventral or oral surface an oblique

funnel-shaped depression (vestibule) which
leads to the mouth. Note the direction of
the cilia in the vestibule.

4. A blind sac opening into the vestibule by the

mouth ; the oesophagus.

5. At a definite point posterior to the blind end

of the oesophagus, the anal spot, where
waste matters are at times passed out from
the body.

II. Structure.

1. Ectoplasm : the sharply defined outer layer,
with a delicate surrounding membrane, the



2. Entoplasm : the more granular, inner portion.

3. At the base of the vestibule the mouth-open-

ing leads into a blind pouch, the oesophagus,
through whose posterior wall the food
passes into the entoplasm.

4. Food-vacuoles : spherical spaces in the ento-

plasm containing water and food-particles.

5. Water-vacuoles.

6. Contractile vacuoles : one near the anterior and

the other near the posterior end. (Study
carefully, and sketch in two or three stages.)

7. Nucleus : an oval body near the centre of

the cell (not always visible in the living
state), the macronucleus ; close to this the
/Sketch a Paramcecium, much enlarged.

III. Movements.

1. Currents in the entoplasm : made evident by

changes in the position of the food-vacuoles
and the water-vacuoles.

2. Action of the cilia. (To see the currents pro-

duced by the cilia in the surrounding water
introduce under the cover-glass a small quan-
tity of powdered carmine. )

Make a diagram of the animal, and indicate by
means of arrows the course of the currents.

IV. Reproduction.

Sketch any specimens you may find dividing by
fission or conjugating.


V. Chemical Experiments.

Treat with 2 per cent, acetic acid; observe:
macronucleus, micronucleus, and tricho-
To see the cilia, treat with dilute iodine.


Mount in water a fragment of a submerged leaf or
other substance to which vorticelloe are attached.
Examine first with AA 2. Observe form and
movements. Look for a quiet specimen and study
with D 2. When it is extended, observe :

General Characters.

1. Form : bell-shaped. The bell attached by

its smaller end to a stalk.

2. Parts:

(a) The conspicuous rim, the peristome, sur-

rounding :

(b) The disk : which closes the mouth of the


(c) Part of the disk raised above the peri-

stome at one side, the epistome.

(d) Cilia : bordering the peristome and the


(e) A space between the peristome and the

epistome, the vestibule.

(/) The mouth : opening from the vestibule
into :

(g) The oesophagus.

(h) A definite region of the vestibule, the
anal spot, through which waste matter is
passed out from the body (visible only at
the time of passing out of waste matter).



II. Structure.

1. The thin transparent external layer, the


2. The finely granular layer next to the cuticle,

the ectoplasm.

3. The central portion, the entoplasm.

4. Food-vacuoles.

5. Water- vacuoles.

6. The contractile vacuole : generally situated near

the disk.

7. The nucleus : a long slender curved body

(not always visible in the living specimen).

8. The stalk: by which the bell is attached,

consisting of :

(a) An outer transparent sheath continuous

with the cuticle of the bell.

(b) The contractile axial filament, the pro-

longation of the ectoplasm of the bell.
Make a diagrammatic sketch much enlarged.

III. Movements.

1. Of the cilia.

Note the way in which the cilia move, the
currents produced in the water (to see
this draw a few particles of finely pow-
dered carmine under the cover-glass), the
whirling of the carmine particles down
the oesophagus.

2. Of the entoplasm : made evident by the

carrying around of food-vacuoles, etc.


3. Of the animal as a whole.

(a) Method of contraction of stalk and of


(b) Mode of extension of contracted animal.
Make a diagram of an expanded and of a con-
tracted animal and label corresponding parts.

Make diagrams of stalk (a) in extended state ;

(b) when contracted.
IV. Reproduction.
Search for :

1. Specimens dividing by fission.

2. Motile forms. When found study with D 2.

Observe the secondary band of cilia. Look
for the contractile vacuole.

3. Conjugation : the union of a small motile

individual with a larger sedentary form.
Y. Chemical Experiment.

1. Stain with iodine ; record the result.



Put upon a slide a drop of liquid that contains
actively growing yeast (e.g. brewer's yeast or
compressed yeast in Pasteur's fluid], cover and
examine, with a low power. Note :

I. General Characters.

1. Aggregations of cells into groups.

2. In the larger individuals protuberances par-

tially constricted off, buds.
Study ivitli a high power, and observe :

3. Form.

4. Mode of union.

5. Size. (Measure.)

II. Structure.

1. Cell-wall.

2. Cell-contents.

(a) Protoplasm (cytoplasm) : granular, with

shining spherules.

(b) Nucleus (not visible in the living state.

See demonstration of prepared speci-

(c) Yacuoles : note the number and size.
Sketch (X 10).

* For methods of staining, etc., see "General Biology," by
Sedgwick and Wilson, second edition, 1895, p. 219.



III. Reproduction.

1. Soiv a few cells of freshly moistened compressed

yeast in a few drops of Pasteur's fluid on a

slide. Cover, and examine with a high power.

Compare the structure of the cells with that

of growing yeast.

Put the slide on a zinc rack, stand the rack in a
dish containing half an inch of water, and cover
with a bell-jar (inoist chamber).
Examine from day to day to see multiplication
by budding. (Gemmation.)

2. Examine with a high power yeast-cells in which

ascospores have been formed. (Endogenous

IV. Chemical Experiments.

1. Mount in water on a slide a very small

amount of powdered starch. Look at it with
a low power. Draw iodine solution under
the cover-glass. Look again ; note the
effect of iodine solution upon starch.

2. In the same way treat yeast upon the slide

with iodine. What inference is to be
drawn as to the presence of starch loithin
the yeast-cell ?

3. Treat another specimen of yeast with magenta

solution. What parts of the yeast plant are
stained ?


4. Crush the cells stained with magenta by press-
ing forcibly on the cover-glass with the
handle of scalpel or needle-holder. What
details of structure (see above, II. 1 and 2)
are visible after crushing ? Does the ma-
genta affect all parts of the cell equally ?
Y. Physiology.

1. Put a large drop of yeast into each of three

test-tubes (previously labelled) containing

(a) Distilled water ;

(b) Pasteur's fluid without sugar ;

(c) Pasteur's fluid with sugar.

Stop the tubes with cotton and keep side by
side. Examine the tubes from day to day
with the naked eye. Record the result and

2. Put a drop of yeast into each of two test-tubes

of the same size (previously labelled) con-
taining equal amounts of Pasteur's fluid
with sugar. Stop both well with cotton.
Boil one for five minutes. Keep them side
by side. Examine the tubes with the naked
eye from day to day. Record the result
and the explanation.


Observe Penicillium growing upon bread in a moist
aim osphere. * Note :

I. General Characters.

Velvety-looking surface, white in young
specimens, dull bluish green in older

Touch a mass of Penicillium spores ivith a needle-
point, and dip the needle-point into a drop
of water upon a slide. Cover, and examine
with a low and then ivith a high power.
Note :

Size. (Measure.)

In the same way sow some spores in Pasteur's
fluid in a watch-glass. Put the watch-glass into
a moist chamber. With a hand -lens watch
the development of the mycelium from day to

II. Structure.

Examine germinating spores (sown twenty-four
hours previously in a vessel of Pasteur's fluid).

Observe and sketch a series of stages in the germina-
tion of the spores, noting :

* To obtain Penicillium, keep a cut lemon for a few days in a
moist atmosphere.



1. Formation of hyphae.

(a) Cell-wall.

(b) Protoplasm.

(c) Vacuoles.

(d) Fat-drops.

Mount in water a portion of mycelium from bread.
Observe :

2. Hyphse.

(a) Division into cells.

(b) Mode of branching. From what part of

a cell does a branch arise ?

(c) Vacuoles.

III. Keproduction.

Aerial hyphse and conidiophores.
Tease out in ivater some of the mycelium from a
specimen that has become only slightly green.
Observe :
1. Erect hyphse, each consisting of :

(a) Primary erect hypha.

(b) Branches. (Terminal branches : basidia

or sterigmata.)

(c) Constrictions of the terminal branches :

spores (conidia). At which end of the
chain are the conidia larger? At
which end are they first formed ?


I. External Characters.

Examine ivith the naked eye the thallus of a green
foliaceous lichen e.g., Parmelia that has been
moistened tuith loater for several hours. Observe :

1. Form.

2. Color.
Sketch afeiv lobes.

With a scalpel carefully separate part of a thallus
from the substratum. Observe :

3. The difference in color between the two sides.
Place the specimen uncovered on a slide, the lower

surface uppermost, and examine with AA 2 by
reflected light. Observe:

4. Ehizoids. (Many will have been broken off

and only their bases will show.)

II. Structure.
1. Sections.

With a razor make sections through the thick part
of a thallus ; or, the specimen may be rolled up
closely and, cross -sections of the roll may be made.
Mount (in ivater) so as to shoiv the cut surface.
Examine with A A 2 in strong reflected light
Observe :

(a) A thin white superficial layer : the upper

cortical layer.

(b) A green layer : gonidial layer.



(c) A thick, pure white layer : medullary


(d) A dark-colored, external layer : lower

cortical layer.


2. Place a small piece of the thallus in water on a
slide and tear it apart ivith needles as com-
pletely as possible. Cover and examine ivith
D 2. Observe :

(a) The hyphse. Disregard the broken frag-

ments and search for specimens in their
natural condition.

(b) The gonidia. Observe : .

Cell wall.


Nucleus (not always visible).
Sketch a few hyphse and gonidia to show their
form, their relative size, and the manner in
which they are connected.


I. External Characters.


1. The vertical stalk, or stipe.

2. The umbrella-like cap, the pileus.

3. The ring, or annulus, around the stalk, the

remains of the membrane, the velum, con-
necting the pileus with the stipe and torn
by the extension of the pileus.

4. The underground mycelium from which the

stipe arises.

5. On the lower surface of the pileus radiating

vertical plates or lamellae.

II. Structure.

Tease out in ivater a piece of the stalk.

1. Note the hyphge of which it is composed.

Examine under the low poiver the surface of a

2. Note the spores ; sometimes in groups of,


Cut in pith cross-sections of a lamella.

3. The centre of the lamella, made up of hyphae

running parallel to the surface.



4. The surface of the lamella consisting of

hyphse at right angles to the surface.

5. The swollen ends of many of the hyphse bear

four small awl-like points, the sterigmata,

each with a single spore.

Tease out in water some of the underground

6. Note the hyphae.



Mix some India ink or jmely powdered gam-
boge with water and examine a drop with a
high power.

Note that when the currents in the water have
ceased the particles of gamboge do not move
from place to place.

Now observe the vibration or oscillation of the
lifeless particles (Brownian movement).


I. Active Bacteria.

Examine with the highest power a drop of hay
infusion or of other liquid containing active
'bacteria. Observe :

1. Form.

2. Size. (Measure).

3. Structure. ( What points of structure are vis-

ible ?)

4. Movements.

(a) Brownian movement.

(b) Active movement from place to place.
Treat with iodine.

Does the iodine bring out any details of
structure. What is its effect upon the
movements of the bacteria?



II. Resting Bacteria Zooglsea Stage.

Examine the scum (zodglcea) from the surface of
hay or of other infusions, or of aquaria, etc.
Observe :

The multitudes of motionless bacteria im-
bedded in a gelatinous substance.

III. Cover-glass Preparation.

With the forceps hold a perfectly clean cover-glass
nearly horizontal and bring its lower side just
into contact with the surface of the liquid con-
taining bacteria (the best results are from a
scum that is only just visible). Put the cover -
glass, wet side uppermost, on a piece of filter-
paper slightly inclined in order that the water
may drain off. When the cover-glass is dry,
pass it quickly three times through a flame y
put a drop of methyl violet upon the cover-
glass j after three or four minutes rinse off
with distilled water; invert the cover-glass
upon a drop of water on a slide and examine
with a high power. Observe :
The deeply stained bacteria.
The differences in form and size.

Sketch a few of each form.
IY. Experiments.

1 . Clean a potato thoroughly, sterilize it in steam
for an hour, and cut it lengthwise into halves
with a knife sterilized in the flame of
a Bunsen burner. Put the halves on a


sterilized glass plate and expose the cut sur-
face to the air for an hour. A.t the end of
this time cover with a hell-jar that has been
sterilized, and put under this some (steril-
ized) liquid to make a moist atmosphere.

Examine from day to day for ten days or

two weeks. Record results and explanation.

Put some freshly-made hay infusion into

e/ / *7 t/

three (previously labelled) test-tubes (a), (b),
(c). Stop them securely with cotton.

(a) To be set aside.

(b) To be boiled once for 3-5 minutes.

(c) To be boiled for 35 minutes three or

four times at intervals of nine or
ten hours.

Keep all three side by side. Watch carefully
for any changes that may appear. Describe
briefly, with explanation.


I. General Characters.

Observe with the naked eye. Note :

1. Floating masses consisting of long, fine, green

Take between the fingers and note the smooth,

slippery feeling.
J^fount a small quantity , in water on a slide , cover ,

and examine with a low power. Note :

2. Unbranched filaments.

(a) The shape of the cells.

(b) The way in which they are joined.

(c) The difference between the terminal

cell and the other cells of the fila-
With a high power observe :

2 4 5 6 7 8

Online LibraryHarriet RandolphLaboratory directions in general biology → online text (page 2 of 8)