Charles Wesley Hargitt.

Outlines of general biology ; an introductory laboratory manual online

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Southern Branch
of the

University of California

Los Angeles







This book is DUE on the last date stamped below



OCT 1 5 lS2i.
NOV 1 31021
8



MAR 19 1928



MAR 1 8 1.927
#61 " I ftp






NOV 5



1941



Form L-9-15n-8,'24



OUTLINES OF

GENERAL BIOLOGY

AN INTRODUCTORY LABORATORY MANUAL



BY

CHARLES W. HARGITT

RESEARCH PROFESSOR OF ZOOLOGY IN SYRACUSE UNIVERSITY

AND

GEORGE T. HARGITT

PROFESSOR OF ZOOLOGY IN SYRACUSE UNIVERSITY



FOURTH EDITION




LEA & FEBIGER

PHILADELPHIA AND NEW YORK



641S6



COPYRIGHT

LEA & FEBIGER

1922



PRINTED IN U. S. A.



QM

3 1-7

USLO.



PEEP ACE TO THE FOURTH EDITION.



IN preparing the present edition little change has been
made; such errors as have been brought to notice have
been corrected, and some changes have been made in the
interest of greater clearness or more precise directions.

The ideal underlying the manual is, as it always has been,
to stimulate inquiry and develop the scientific habit of
work and thought. The order of presentation remains
unchanged, for both from practical and pedagogical reasons
such an arrangement has justified itself through years of
experience. The order of presentation of topics is, however,
of secondary importance, and the individual teacher will
make such choice of topics and order of study as best
meets his needs.

An elementary course in biology must of necessity be
limited to relatively few typical organisms, but the aim of
the manual is distinctly not the study of types as such.
In our own course the laboratory study is planned to illus-
trate general biological principles such as the following:
fundamental plans of animal structure; homology; adap-
tation; protoplasmic structure and behavior; development
of organisms; and other similar principles. In conducting
such a course it is necessary to make definite plans ahead
of time, and select from the manual those topics which cover
the desired ground. It is believed that there is sufficient
material included to make possible a considerable choice to
meet varied needs and desires.



vi PREFACE TO THE FOURTH EDITION

It is still a pleasure to acknowledge the cordial cooperation
among other members of the zoological staff in such sug-
gestions as their several experiences and observations have
prompted. Should others who use the book feel disposed to
offer suggestions touching either the matter or the method
of the manual they may be assured of the cordial thanks of
the authors.

C. W. H.

G. T. H.

SYBACUSE, 1922



CONTENTS.



INTRODUCTION:

LABORATORY AND APPARATUS 17

NOTES AND DRAWINGS 18

DISSECTION 21

THE MICROSCOPE 22

FROG 26

ORGANS, TISSUES AND CELLS 45

PROTOPLASM 47

CELL (CYTOLOGY) 50

AMCEBA 54

PARAMECIUM 57

VORTICELLA 62

QUESTIONS ON THE PROTOZOA IN GENERAL 64

PLEUROCOCCUS 66

COLONIAL PROTOZOA 68

SPIROGYRA 70

SPONGE 73

HYDRA 75

HYDROID:

PENNARIA 80

OBELLA 83

MEDUSA 85

EARTHWORM 87

SAND WORM 95

FERN . 98

YEAST 104

BACTERIA 107

CRAYFISH 110

GRASSHOPPER 116

HONEYBEE 121

CLAM 125

SNAIL 133

FISH 135

CLASSIFICATION . 140



ar

viii CONTENTS

. APPE- DIX:

OLLECTION AND PREPARATION OF MATERIAL 147

PREPARATION AND MOUNTING OF SLIDES 153

REAGENTS 155

TESTS FOR ORGANIC SUBSTANCES 161

GLOSSARY 163

INDEX . 179



GENERAL BIOLOGY.



INTRODUCTION

Laboratory and Apparatus

IN order to get the best results in a laboratory course
there should be cordial cooperation between students and
instructors. The laboratory should be orderly and attractive,
and its schedule regarded with the same promptness and
fidelity as that of the classroom. Certain apparatus is
assigned to each student who must be responsible for it
during use. Notebooks, dissecting instruments, pencils,
and the laboratory manual, are to be furnished by each
student. Each is expected to do his work independently,
faithfully, and to have his own outfit which should be kept
in the best possible condition for effective use.

Ample laboratory material is furnished for the work
required, but it should be used with reasonable economy.
This relates to reagents as well as specimens. Let there be
particular care in the handling of models or museum speci-
mens placed upon the demonstration table. These are not
to be removed from this table without express permission.
The same applies to demonstration materials and dissections.

At the close of the laboratory period, which may be ex-
tended to students desirous of doing extra work, let the
tables be cleared up, the instruments, dissecting pans and
2



18 GENERAL BIOLOGY

the like put in the proper places, all solid waste deposited
in receptacles for that purpose, and only water or liquid
waste thrown into the sinks.

Notes and Drawings

Experience has shown that it is necessary to make accurate
drawings and to write a definite and careful description of
an animal if one is to secure a satisfactory knowledge of it.
The drawings should be made (on one side only) on un-
ruled heavy paper, or cardboard, with a drawing pencil
(about 3H); the notes, written on separate sheets, should
accompany the drawings.




FIG. 1.

Figs. 1 to 3 are from drawings which are correct in form,
accurate in structure, and satisfactory from a scientific
point of view. The drawings made to accompany the work
of this course should be in outline like the figures, since
shading tends to obscure rather than clarify the details of
structure. The drawings shown in the figures demonstrate
the clearness with which details are shown, even when the
structure is rather complex. However, it is sometimes
desirable to represent the texture of a part and a shaded
drawing will occasionally be necessary. Fig. 4 is a drawing
of a group of cells characterized by thick walls of rather
definite appearance and structure. One side of the draw-



INTRODUCTION



10



ing is in outline and shows clearly the shape and arrange-
ment of the cells and the thickness of their walls. The




Fig. 2.




FIQ. 3.



20



GENERAL BIOLOGY



shaded portion illustrates the further detail of a certain
structure in the walls. Fig. 5, a cell in the process of divi-
sion, is shaded in a manner which will bring out the details
of cellular structure.

The following suggestion may be helpful: Make the
drawings large, leave considerable space between them and
have them symmetrically arranged on the page. In start-





FIG. 4.



FIG. 5.



ing a drawing make all lines very faint, and when the form,
proportions and arrangement of parts is satisfactory go over
the lines with a smooth continuous stroke, producing a line
of the desired strength. The drawing must represent the
actual specimen studied, should show the real structure
rather than the mere appearance, and should be finished
in the laboratory while the specimen is under observation.



INTRODUCTION 21

Give each preparation careful study before starting a draw-
ing.

The directions for laboratory study are merely suggestions
with regard to methods and order of work; the specimen is
the thing being studied. Do not be afraid to do some things,
or to make some drawings not asked for in the outlines, if
you can thereby get a clearer idea of the structure or add
further to your knowledge of the animal. Most of the
questions asked in the outlines can be answered from the
specimen if the search is made, but if help is necessary call
upon the instructor for aid.

Always give a clear and definite title to each drawing,
indicating what aspect of the specimen is shown; also clearly
name the parts shown in the drawing. Write labels parallel
to the bottom of the page and connect to the part desired by
faint continuous lines (these are better than dotted lines).
The title of the drawing should be followed by an indication
of the scale of the drawing, e. g. x | means one-half the
natural size, x 5 means five times natural size.

Dissection

The object of dissection is to separate the various organs
or parts in such a way as to show their form and relation
to each other. It consists largely in removing the con-
nective tissue which holds the parts together.

Fix the specimen firmly in a position that will be con-
venient for work, usually with the head away from you.
If pins are used stick them obliquely into the wax of the
dissecting pan. Large specimens should be moistened from
time to time to keep from drying, and small animals should
be dissected under water.

Before starting a dissection study the specimen care-



22 GENERAL BIOLOGY

fully and note where the cut may be made to expose the part
wanted with the least injury to the surrounding parts. Do
not grasp nerves or bloodvessels with the forceps, but hold
the tissue at one side of them. Do not allow scraps to
accumulate on the specimen; with a pipette wash away
the debris which gathers on the specimen under water, and
change the water frequently.

Instruments must be kept clean and sharp to accomplish
the best results, therefore do not use scissors or scalpel to
cut hard objects and do not allow the instruments to be-
come rusty.

Clean and dry the instruments, after using, and smear
them with a little oil or vaseline.

The scissors are used almost exclusively when cutting is
to be done. Each blade of the scissors holds the object for
the other blade, whereas the scalpel tends to push out of
the way the object to be cut, and also often leads to the
cutting of underlying tissues that should not be injured.
While cutting with one hand, whether with the scissors or
scalpel, always use the forceps in the other to steady the
object and to hold the edge of the cut.

The Microscope

Since the compound microscope is the instrument most
indispensable to the biological student some knowledge of
its construction and manipulation should precede its im-
mediate application to the work in which it is used. The
following study of its parts and their relations may there-
fore be made in the order indicated.

1. Parts, (a) The base, a heavy support bearing (6) the
column to which is fastened (c) the stage, a horizontal sup-
port for objects to be examined. In the center of the stage



INTRODUCTION 23

is an opening for the passage of light by which an object is
to be illuminated. It is provided with clips for firmly
holding the object in position during its study. Situated
just under the lower side of the stage is a mechanism, (d)
the diaphragm, for regulating the amount of light admitted
to the object. Note that these diaphragms may be of
different types, mere disks to be inserted in the stage, or a
circular disk to be rotated, or a shutter-like device known
as the iris diaphragm, (e) Attached to a movable arm
under the stage is the mirror by which light is reflected through
the object and lens to the eye of the observer. Note that
it is double, having on one side a plane, and on the other
a concave surface; the latter serves to concentrate more
light upon the object, and should be used chiefly with the
high power lenses.

Above the stage is (/) the tube supported on the arm of
the microscope. The tube is a means of attaching the
optical parts, i. e., the lenses, of which there are several;
those at the upper end being called the oculars or eye-pieces
since they relate directly to the eye of the observer; those
attached to the lower end known as the objectives, since
they relate to the object under observation. The wheel-
like parts working on the side of the arm, and a similar
smaller one at the top or side, have to do with focusing to
be explained later.

2. Adjustments. These refer to the matter of so relating
the mirror, the object to be studied, the lenses employed,
the amount of light admitted, that clear and distinct images
are afforded. First in the process is that of light, and
practice will be required in order to learn its importance.
This will involve testing the effects of both plane and con-
cave mirrors, the use of the diaphragm in regulating the
amount of light, and finally that adjustment of the lenses



24 GENERAL BIOLOGY

known as focusing. In the last of these operations will be
involved learning the uses of the so-called coarse and fine
adjustments, the former effected by means of the rack motion
produced by the large milled heads at the side of the arm,
and the second by means of the small milled head at the top
or side. Try out all these operations in a general way and
finally under the directions of the next section.

3. Focusing. The object to be examined must be thin,
since the light must pass through it. The object is placed
on a glass slide, with a drop of water or other liquid, and
covered with a thin glass cover. Place the slide on the stage
with the object directly over the center of the opening.
Move the low power objective rather close to the slide and,
while looking into the eyepiece, turn the coarse adjustment
so as to raise the tube until the object comes into view,
now using the fine adjustment focus carefully until the image
is perfectly sharp.

The high power, w y hen in focus, is so close to the cover
glass that great care must be used in adjusting it or it may
be injured. Turn the nose piece slowly to bring this ob-
jective into position, taking care to see that it does not
touch the cover glass. If it swings into position without
striking, a slight movement of the fine adjustment will usually
bring the image into sharp focus. If the high pow r er can-
not be swung into position the same process of focusing
must be used as for the low power. Always focus upward,
since to do the contrary may result in the lens striking the
slide to the injury of both the slide and the lens.

Practice these points patiently and with care until every
phase is clearly understood and easily managed. This
practice in manipulation will be time w T ell spent, since later
work will thereby be done easily and skilfully.



INTRODUCTION 25

4. Use and Care of the Microscope. Having learned the
parts and adjustments of the instrument practice their
use until they become familiar. This is especially im-
portant in the adjustments relating to light. Test manip-
ulation of mirrors and diaphragms until able to obtain
and control just the amount and quality of light essential
to the best effects, doing so with eye constantly at the ocular.
The best light is that of the open sky (not sunlight direct)
or that reflected from bright clouds. Artificial light may
be used provided a screen of some sort be interposed, such
as a bluish, or ground glass. Begin every study with the
low power, nothing is gained by using a higher power than
serves the end in view.

To avoid eye fatigue while using the microscope practice
looking with both eyes open, which after a little practice
is not especially difficult. If not easily acquired, an artificial
shade or screen may be used as may be explained by the
instructor.

Proper care of the microscope is important if its efficiency
is to be at its best. Keep every part clean, do not allow
water, or dirt, or chemicals, to remain in contact with any
of its parts. This is especially important for the lenses.
Do not touch the lenses with the naked finger, and if they
should appear dirty cleanse with lens paper furnished by
the laboratory. This may be facilitated by breathing on
the lens and then gently wiping dry.

Never attempt to take lenses apart.



THE FROG.

RANA SP.

FROGS may be had at various times of the year, and are
easily kept in proper aquaria, so arranged that the animals
have range from water to dry or rocky support, provided
care is taken to guard against serious contamination of tank
or water. They may be secured in late summer or fall, or
even in spring, though in New York State there is now a
closed season in the spring as for other game animals. In
addition to living specimens kept during the year there
should also be an ample supply of preserved material for
the needs of classes. If specimens are to be injected for
study of the blood system this must be done immediately
after killing preparatory to preservation.

In the neighborhood of larger cities frogs may often be
secured through fish markets, provided attention is given
to the subject in ample time, and often at prices much lower
than those charged by professional supply departments.

I. External Characters.

What is the shape of the body as a whole? Are dorsal
and ventral surfaces well marked? How? Note the di-
vision of the animal into head, trunk, and limbs. Is there
a neck and tail? What is the character of the skin? In
the living animal is the skin moist or dry, warm or cold?
Are there scales or other protective structures in the skin?

1. Head. Note its triangular shape. Observe the follow-
ing parts : mouth, nostrils, eyes, ear-drum or tympanic mem-



THE FROG 27

brane. Do the eyes have lids? How many? Which
moves in the living frog? Draw the head from the side.

2. Trunk. Note the shape and the differences in the
dorsal and ventral sides.

3. Limbs. Note the number and arrangement. In the
hand. How many digits or fingers? The hind limb is
fore limbs the following divisions occur: arm, forearm,
divided into thigh, leg, and foot. How many digits? - How
is the leg adapted for swimming? Compare with the fore
limb in length and number of digits. Draw both fore and
hind leg.

4. External Apertures. Note the position, shape and size
of the following: mouth, anus, nostrils.

II. Mouth Cavity.

Open the mouth to its full extent, cutting the corners of
the jaw if necessary. Are there lips? Is there a tongue?
What is its shape, size and mode of attachment? Where,
are the teeth found? Teeth on the jaw bones are called
maxillary teeth, those on the roof of the mouth are vomerine
teeth. Pass a bristle through the outer nostrils and observe
the inner or posterior nostrils. Where are they found?
Pierce the tympanic membrane and pass a blunt probe into
the, ear; in the mouth cavity the place where the probe
appears is the opening of the Eustachian tube.

In the posterior floor of the mouth just at the end of the
tongue is a slit, the glottis, opening into the trachea and
lungs. Its margin is stiff and cartilaginous, and the opening
is closed except when air is passing. The esophagus lies
dorsal to the glottis. Compare with the latter.

Make a drawing of the mouth cavity, showing all the
points referred to.



28 ' GENERAL BIOLOGY

m. Internal Anatomy.

Fasten the frog in the dissecting pan on its back, and slit
the skin the entire length of the body in the median line.
Is the skin loosely or closely attached to the body? The
spaces that are found beneath the skin are lymph spaces.
Laying back the skin observe the walls of the abdomen,
made up of muscles. Determine the points of attachment
of these muscles. In what directions do the fibers of the
muscles extend on the ventral wall, and on the side wall?
The ventral muscles are the straight abdominal, and those
of the side walls are the oblique abdominal muscles. Also
observe the group of pectoral or breast muscles in the region
of the arm. Is this one muscle or a group of muscles ? What
is the probable function of these muscles?

Draw the ventral surface of the frog, showing the muscles
just studied. If time permits, the muscles of one of the
hind legs may be studied and a drawing made.

Cut through the body wall, taking care not to injure the
organs lying beneath. Notice that the internal organs lie
in a large cavity, the body cavity or ccelom. Pin back the
flaps and observe the following organs which are exposed:

1. Heart. In the median line beneath the pectoral girdle.
It has two thin-walled auricles and a thicker-walled ven-
tricle, the whole being enclosed in a delicate sac, the peri-
cardium. If the heart is beating record the order of the
pulsations of the different chambers. From the ventricle
a large vessel, the truncus arteriosus, extends obliquely for-
ward over the auricles. On the dorsal side of the heart is
a thin, triangular sac, the sinus venosus, into which the blood
comes before entering the heart. Does the sinus com-
municate with the auricles or the ventricle?

Make drawings of the heart to show these points.



THE FROG 29

2. Liver. A large, dark red mass, dorsal to the heart.
What is its size and shape? Of how many lobes is it com-
posed? Between the lobes is the bile sac, .or gall bladder.
The cystic ducts are tubes which lead from the liver to the
bile sac and the bile duct extends from the bile sac through
the pancreas to the digestive tube, which it enters about
half an inch posterior to the stomach. Turn the liver for-
ward and trace the bile duct to its opening into the intestine.

Make a drawing of this region.

(If the specimen is a female take up, at this point, the
study of the reproductive organs. Having shown their
position, size and structure in a drawing, remove them and
study further the other organs of the body cavity.)

3. Lungs. Two thin-walled sacs dorsal to the liver and
at the sides of the esophagus. Note the texture pf the walls
and the character of the lining. The lungs may be expanded
by blowing air into them.

4. Stomach. Note the shape, size and position. How 7
is the stomach held in place? Slit the stomach longitudi-
nally, and determine the character of its walls and its lining.

5. Intestine. Is it straight or coiled? How is it held in
position? Compare the walls with those of the stomach.
Near the posterior end note an enlargement, the large intestine.

6. Pancreas. A pale mass lying in the loop made by
stomach and intestine. Show its position in the drawing
made of the liver.

7. Spleen. A small round body lying in the posterior
part of the body. Does it appear to be joined to, or connected
with any other organ?

8. Bladder. A thin walled sac in the extreme posterior
part of the body cavity. What is its shape? With what
organs does it communicate?

Make a drawing to show the organs so far studied.



30 GENERAL BIOLOGY

9. Ovaries. Found in the female and composed of masses
of eggs, their size depending upon the maturity of the animal,
and the time of year. If the ovaries are mature they may
almost completely fill the body cavity crowding all the other
organs that are in the cavity. If the animal is immature
the small ovaries will be found near the dorsal part of the
body cavity hidden by the digestive organs. Long con-
voluted tubes along the dorsal wall of the body cavity are
the oviducts. Anteriorly these are held in place against
the esophagus, and open into the coelom by a funnel-shaped
mouth. Near the posterior end each oviduct enlarges to
form a sort of bladder, called the uterus.

Fastened near the anterior end of the ovaries are slender
yellowish fat bodies.

10. Testes. These organs, the male reproductive organs,
are oval yellowish bodies near the dorsal body wall. Usually
connected to them are slender yellowish fat bodies. Ducts
from the testes pass into the kidneys and communicate
with the urinary duct or ureter. The ureter, therefore,
functions as a common urino-genital duct. Rudiments of
oviducts may occasionally be present along the sides of the
kidneys.

11. Kidneys. To study the kidneys and their ducts,
remove the muscle and a portion of the bony pelvic girdle
which lie ventral to the intestine and cloaca. Place the
animal under water and displace the other organs to expose
the kidneys, a pair of elongated reddish organs situated
close to the vertebral column. A small tube, the ureter,
extends from the posterior end of each kidney to the cloaca.
On the ventral side of each kidney is a narrow yellowish
line, the adrenal body, a gland whose secretion is poured
into the blood.



THE FROG 31

12. Cloaca. The cloaca is a continuation of the large
intestine, and opens to the outside on the dorsal side of the
animal. Expose the cloaca and note the connection of
the bladder, ureters, and oviducts with it.

A diagrammatic drawing made from the side will show
the relations of these ducts to each other and to the cloaca;
or a drawing on a large scale, from the ventral side will be
satisfactory if some parts are slightly displaced.

Observe the peritoneum, a pigmented membrane which
lines the ccelom. This also covers the organs, and makes
up the mesenteries which hold the various organs in position.

IV. Circulatory System.

This system must be worked out from specimens whose
vessels have been filled with a colored injection mass. Such
an injection expands the bloodvessels and causes them to
stand out clearly from surrounding tissues and organs. If
an injected animal is not used only a few of the larger vessels


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Online LibraryCharles Wesley HargittOutlines of general biology ; an introductory laboratory manual → online text (page 1 of 10)