I, I Kit AH Y
itg 0! California,
University of California.
ZENTMAYER'S LARGEST MICROSCOPE.
ONE-THIRD ACTUAL SIZE.
MANUAL OF MICROSCOPY
COMPENDIUM OF THE MICROSCOPIC SCIENCES,
MICRO-MINERALOGY, MICRO-CHEMISTRY, BIOLOGY, HISTOLOGY,
AND PATHOLOGICAL HISTOLOGY.
KEWKITTEN AND GEEATLY ENLAKGED.
TWO HUNDRED AND FIVE ILLUSTRATIONS.
J. H. WYTHE, A.M., M.D.,
PROFESSOR OF MICROSCOPY AND BIOLOGY IN THE MEDICAL COLLEGE OF THE PACIFIC,
LINDSAY & BLAKISTON.
Entered according to Act of Congress, in the year 1877,
By LINDSAY & BLAKISTON,
In the office of the Librarian of Congress at Washington, D. C.
SHERMAN & CO., PRINTERS.
TO THE -
SAN FRANCISCO MICROSCOPICAL SOCIETY,
AS A TESTIMONY
ZEAL AND INDUSTRY OF ITS MEMBERS
IN THE PROSECUTION
THE progress of microscopic science may be well illus-
trated by a comparison between the present and former
editions of this book. The author's intention was to
place within the reach of the student of nature a com-
pendium of microscopy, free from unnecessary verbiage,
which should aid in every department of natural science.
It is 110 small compliment to such a work that for a
quarter of a century it should hold a place among works
of reference, although surrounded by larger and more
pretentious volumes. In order to meet the request of
the publishers for another edition, it has been found
necessary to rewrite the entire book, and although the
original design has been kept in view, the numerous
additions to our science render considerable enlargement
needful, notwithstanding the effort made to concentrate
the material into the smallest compass consistent with
The vision of microscopy sweeps over all the world,
and embraces all forms of organic and inorganic ex-
istence. To give directions respecting most approved
methods, and to classify the most important facts, has
required labor, which it is hoped will result in rendering
the work a necessary companion to the student, and an
aid to the progress of real science.
Many of the figures illustrating the lower forms of life,
and normal and pathological histology, have been drawn
from the works of Carpenter, Beale, Frey, Strieker, Bill-
roth, and Rindfleisch, to which the more advanced stu-
dent is referred for further details.
HISTORY AND IMPORTANCE or MICROSCOPY.
Application of the Microscope to Science and Art Progress of Micros-
copy, . . 17-21
The Simple Microscope Chromatic and Spherical Aberration Com-
pound Microscope Achromatic Object-glasses Eye-pieces Me-
chanical Arrangements Binocular Microscope, . . . 21-32
Diaphragms Condensers Oblique Illuminators Dark-ground ditto
Illumination of Opaque Objects Measuring and Drawing Objects
Standards of Measurement Moist Chamber Gas Chamber Warm
Stage Polari scope Microspectroscope Nose-piece Object-finders
Micro-photography, ........ 32-48
USE OP THE MICROSCOPE.
Care of the Instrument Care of the Eyes Table Light Adjustments
Errors of Interpretation Testing the Microscope, . . 48-58
MODERN METHODS OF EXAMINATION.
Preliminary Preparation of Objects Minute Dissection Preparation
of Loose Textures Preparation by Teasing Preparation by Section
Staining Tissues Injecting Tissues Preparation in Vi>cid Media
Fluid Media Indifferent Fluids Chemical Reagents Staining
Fluids Injecting Fluids Preservative Fluids Cements, . 58-76
MOUNTING AND PRESERVING MICROSCOPIC OBJECTS.
Opaque Objects Cells Dry Objects Mounting in Balsam or Dammar
Mounting in Fluid Cabinets Collecting Objects Aquaria, 76-83
THE MICROSCOPE IN MINERALOGY AND GEOLOGY.
Preparation of Specimens Examination of Specimens Crystalline
Forms Crystals witbin Crystals Cavities in Crystals Use of Po-
larized Light Origin of Rock Specimens Materials of Organic
Origin Microscopic Paleontology, ..... 84-98
THE MICROSCOPE IN CHEMISTRY.
Apparatus and Modes of Investigation Preparation of Crystals for the
Polariscope Use of the Microspectroscope Inverted Microscope
General Micro-chemical Tests Determination of Substances Al-
kalies Acids Metallic Oxides Alkaloids Crystalline Forms of
THE MICROSCOPE IN BIOLOGY.
Theories of Life Elementary Unitor Cell Cell-structureand Formation
Phenomena of Bioplasm Movements of Cells Microscopic Dem-
onstration of Bioplasm Chemistry of Cells and their Products Va-
rieties of Bioplasm Cell-genesis Reproduction in Higher Organ-
isms Alternation of Generations Parthenogenesis Transforma-
tion and Metamorphosis Discrimination of Living Forms, 116-127
THE MICROSCOPE IN VEGETABLE HISTOLOGY AND BOTANY.
Molecular Coalescence Cell-substance in Vegetables Cell- wall or Mem-
brane Ligneous Tissue Spiral Vessels Laticiferous Vessels Si-
liceous Structures Formed Material in Cells Forms of Vegetable
Cells Botanical Arrangement of Plants Fungi Protopbytes
Desmids Diatoms Nostoc Oscillatoria Examination of the
Higher Cryptogamia Examination of Higher Plants, . 128-157
THE MICROSCOPE IN ZOOLOGY.
Monera Rhizopods Infusoria Rotatoria Polyps Hydroids Aca-
lephs Echinoderms Bryozoa Tunicata Conchifera Gastero-
poda Cephalopoda Entozoa Annulata Crustacea Insects
Arachnida Classification of the Invertebrata, . . . 158-182
THE MICROSCOPE IN ANIMAL HISTOLOGY.
Histo-chemistry Histological Structure Simple Tissues Blood
Lymph and Chyle Mucus Epithelium Hair and Nails Enamel
Connective Tissues Compound Tissues Muscle Nerve Glan-
dular and Vascular Tissue Development of the Tissues Digestive
and Circulatory Organs Secretive Organs Respiratory Organs
Generative Organs Locomotive Organs Sensory Organs Organs
of Special Sense Suggestions for Practice, . . . 182-226
THE MICROSCOPE IN PRACTICAL MEDICINE AND PATHOLOGY.
Microscopic Appearances after Death of the Tissues Morbid Action in
Tissues New Formations Examination of Urinary Deposits
Human Parasites Examination of Sputa Microscopic Hints in
Materia Medica and Pharmacy, ..... 226-245
1 1 B R A R Y
HISTORY AND IMPORTANCE OF MICROSCOPY.
THE term microscopy, meaning the use of the micro-
scope, is also applied to the knowledge obtained by this
instrument, and in this sense is commensurate with a
knowledge of the minute structure of the universe, so far
as it may come under human observation. Physics and
astronomy treat of the general arrangement and motions
of masses of matter, chemistry investigates their constitu-
tion, and microscopy determines their minute structure.
The science of histology, so important to anatomy and
physiology, is wholly the product of microscopy, while
this latter subject lends its aid to almost every other
branch of natural science.
To the student of physical phenomena this subject un-
folds an amazing variety developed from most simple
beginnings, while to the Christian philosopher it gives the
clearest evidence of that Creative Power and Wisdom
before whom great and small are terms without meaning.
In the arts, as well as in scientific investigations, the
microscope is used for the examination and preparation of
delicate w r ork. The jeweller, the engraver, and the miner
find a simple microscope almost essential to their employ-
ments. This application of the magnifying power of lenses
was known to the ancients, as is shown by the glass lens
18 THE MICROSCOPIST.
found at Nineveh, and by the numerous gems and tablets
so finely engraved as to need a magnifying glass to detect
In commerce, the microscope has been used to detect
adulterations in articles of food, drugs, and manufactures.
In a single year $60,000 worth of adulterated drugs was
condemned by the New York inspector, and, so long as
selfishness is an attribute of degraded humanity, so long
will the microscope be needed in this department.
In agriculture and horticulture microscopy affords valu-
able assistance. It has shown us that mildew and rust in
wheat and other food-grains, the " potato disease," and
the "vine disease," are dependent on the growth of minute
parasitic fungi. It has also revealed many of the minute
insects which prey upon our grain-bearing plants and fruit
trees. The damage wrought by these insects in the United
States alone has been estimated by competent observers
as not less than three hundred millions of dollars in each
year. The muscardine, which destroys such large num-
bers of silk-worms in France and other places, is caused
by a microscopic fungus, the Botrytis bassiana.
The mineralogist determines the character of minute
specimens or of thin sections of rock, and the geologist
finds the nature of many fossil remains by their magnified
image in the microscope.
The chemist recognizes with this instrument excessively
minute quantities and reactions which would otherwise
escape observation. Dr. Wormley shows that micro-
chemical analysis detects the reaction of the 10,000th to
the 100,000th part of a grain of hydrocyanic acid, mer-
cury, or arsenic, and very minute quantities of the vege-
table alkaloids may be known by a magnified view of their
sublimates. The micro-spectroscope promises still more
wonderful powers of analysis by the investigation of the
absorption bands in the spectra of different substances.
In biology the wonderful powers of the microscope find
HISTORY AND IMPORTANCE OF MICROSCOPY. 19
their widest range. If we see not life itself, we see its
first beginnings, and the process of its development or
manifestation. If we see not Nature in her undress, we
trace the elementary warp and woof of her mystic drapery.
In vegetable and animal physiology we see, by its
means, not only the elementary unit the foundation-stone
of the building but also chambers and laboratories in
the animated temple, which we should never have sus-
pected tissues and structures not otherwise discoverable
not to speak of species innumerable which are invisible
to the naked eye.
In medical science and jurisprudence the contributions
of microscopy have been so numerous that constant study
in this department is needed by the physician who would
excel or even keep pace with the progress of his profes-
sion. Microscopy may be truly called the guiding genius
of medical science.
Even theology has its contribution from microscopy.
The teleological view of nature, which traces design, re-
ceives from it a multitude of illustrations. In this de-
partment the war between skeptical philosophy and theol-
ogy has waged most fiercely; and if the difference between
living and non-living matter may be demonstrated by the
microscope, as argued by Dr. Beale and others, theology
sends forth a paean of victory from the battlements of this
The attempts made by early microscopists to determine
ultimate structure were of but little value from the im-
perfections of the instruments employed, the natural mis-
takes made in judging the novel appearances presented,
and the treatment to which preparations were subjected.
In late years the optical and mechanical improvements in
microscopes have removed one source of error, but other
sources still remain, rendering careful attention to details
and accurate judgment of phenomena quite essential. Care-
ful manipulation and minute dissection require a knowledge
20 * THE MICROSCOPIST.
of the effects of various physical and chemical agencies, a
steady hand, and a quick-discerning eye. Above all,
microscopy requires a cultured mind, capable of readily
detecting sources of fallacy, and such a love of truth as
enables a man to free himself from all preconceived no-
tions of structure and from all bias in favor of particular
theories and analogies. What result is it possible to draw
from the observations of those who boil, roast, macerate,
putrefy, triturate, and otherwise injure delicate tissues,
except for the purpose of isolating special structures or
learning the effects of such agencies ? Yet many of the
phenomena resulting from such measures have been de-
scribed as primary, and theories of development have been
proposed on the basis of such imperfect knowledge.
Borelli (1608-1656) is considered to be the tirst who
applied the microscope to the examination of animal
structure. Malpighi (1661) first witnessed the actual cir-
.culation of the blood, which demonstrated the truth of
Harvey's reasoning. He also made manj^ accurate obser-
vations in minute anatomy. Lewenhoeck, Swammerdam,
Lyonet, Lieberkuhn, Hewson, and others, labored also in
this department. When we remember that these early
laborers u^ed only simple microscopes, generally of their
own construction, we must admire their patient industry,
skilful manipulation, and accurate judgment. In these
respects they are models to all microscopists.
Within the last quarter of a century microscopic ob-
servers may be numbered by thousands, and some have
attained an eminent reputation. At the present day, in
Germany, England, France, and the United States, the
most careful and elaborate investigations are being made,
older observations are repeated and corrected, new discov-
eries are rapidly announced, and the most hidden recesses
of nature are being explored.
It is proposed in this treatise to give such a resume of
microscopy as shall enable the student in any department
THE MICROSCOPE. 21
to pursue original investigations with a general knowl-
edge of what has been accomplished by others. To this
end a comprehensive view of the necessary instruments
and details of the art, or what the Germans call technol-
ogy, is first given, and then a brief account of the appli-
cation of the microscope to various branches of science,
especially considering the needs of physicians and stu-
dents of medicine.
The Simple Microscope. The magnifying power of a
glass lens (from lens, a lentil ; because made in the shape
of its seeds) was doubtless known to the ancients, but only
in modern times has it been applied in scientific research.
The forms of lenses generally used are the double convex,
with two convex faces ; piano convex, with one face flat
and the other convex ; double concave, with two concave
faces ; plajio-concave, with one flat and one concave face ;
and the meniscus, with a concave and a convex face.
In the early part of the seventeenth century very mi-
nute lenses were used, and even small spherules of glass.
Many of the great discoveries of that period were made
by these means. A narrow strip of glass was softened in
the flame of a spirit-lamp and drawn to a thread, on the
end of which a globule w r as melted and placed in a thin
folded plate of brass, perforated so as to admit the light.
Some of these globules were so small as to magnify sev-
eral hundred diameters. Of course, they were inconve-
nient to use, and larger lenses, ground on a proper tool,
were more common.
The magnifying power of lenses depends on a few simple
22 THE MICROSCOPIST.
optical laws, concerning refraction of light, allowing the
eye to see an object under a larger visual angle ; so that
the power of a simple microscope is in proportion to the
shortness of its focal length, or the distance from the lens
to the point where a distinct image of the object is seen.
This distance may be measured by directly magnifying
an object with the lens, if it be a small one, or by casting
an image of a distant window, candle, etc., upon a paper
or wall. The focus of the lens is the point where the
image is most distinct. Different persons see objects
naturally at different distances, but ten inches is consid-
ered the average distance for the minimum of distinct
vision. A lens, therefore, of two inches focal length,
magnifies five diameters ; of one inch focus, ten diameters ;
of one-half inch, twenty diameters ; of one-eighth inch,
eighty diameters ; etc.
Simple microscopes are now seldom used, except as
hand magnifiers, or for the minute dissection and prepa-
ration of objects. They are used for the latter purpose,
when suitably mounted with a convenient arm, mirror,
etc., because of the inconvenience of larger and otherwise
more perfect instruments.
Single lenses, of large size, are also used for concentra-
ting the light of a lamp on an object during dissection, or
on an opaque object on the stage of a compound micro-
There are imperfections of vision attending the use of
all common lenses, arising from the spherical shape of the
surface of the lens, or from the separation of the colored
rays of light when passing through such a medium.
These imperfections are called respectively spherical and
chromatic aberration. To lessen or destroy these aberra-
tions, various plans have been proposed by opticians. For
reducing spherical aberration, Sir John Herschel pro-
posed a doublet of two plano-convex lenses, whose focal
lengths are as 2.3 to 1, with their convex sides together;
THE MICROSCOPE. 23
and Mr. Coddington invented a lens in the form of a
sphere, cut aw r ay round the centre so as to assume the
shape of an hour-glass. This latter, in a convenient set-
ting, is one of the best pocket microscopes. Dr. Wollas-
ton's doublet consists of two plano-convex lenses, whose
focal lengths are as 1 to 3, with the plane sides of each
and the smallest lens next the object. They should be
about the difference of their focal lengths apart, and a
diaphragm or stop an opaque screen with a hole in it
placed just behind the anterior lens. This performs ad-
mirably, yet has been further improved by Mr. Holland
by making a triplet of plano-convex lenses (Fig. 1), with
the stop between the upper lenses.
The Compound Microscope consists essentially of two
convex lenses, placed some distance apart, so that the
image made by one may be magnified by the other.
These are called the object-glass and the eye-glass. In
Fig. 2, A is the object-glass, which forms a magnified
image at c, which is further enlarged by the eye-glass B.
An additional lens, D, is usually added, to enlarge the
field of view. This is called the field-glass. Its office, as
in the figure, is to collect more of the rays from the
object-glass and form an image at F, which is viewed by
Owing to chromatic aberration, an instrument of this
kind is still imperfect, presenting rings of color round the
edge of the field of view as well as at the edge of the
magnified image of an object, together with dimness and
confusion of vision. This may be partly remedied by a
small hole or stop behind the object-glass, which reduces
the aperture to the central rays alone, yet it is still un-
satisfactory. Some considerable improvement may result
from using Wollaston's doublet as an object-glass, but the
achromatic object-glasses now supplied by good opticians
leave nothing to be desired.
Object-glasses. A general view of an achromatic object-
glass is given in Fig. 3. It is a system of three pairs of
lenses, 1, 2, 3, each composed of a double convex of crown
glass and a plano-concave of flint, a, 6, c, represents the
angle of aperture, or the cone of rays admitted. It is
unnecessary to consider the optical principles which un-
derlie this construction. Different opticians have different
formulae and propose various arrangements of lenses, and
there is room for choice among the multitude of micro-
scopes presented for sale. For high powers, the German
and French opticians have lately proposed a principle of
construction which is known as the immersion system.
It consists in the interposition of a drop of water between
the front lens of the objective and the covering glass over
the object. This form of object-glass is corning into gen-
eral use. For the more perfect performance of an objec-
tive, it is necessary that it should be arranged for correct-
ing the effect of different thicknesses of covering glass.
This is accomplished by a fine screw movement, which
brings the front pair of lenses (1, Fig. 3) nearer or further
from the object. In this way the most distinct and accu-
rate view of an object may be obtained.
26 THE MICROSCOPIST.
Eye pieces. The eye-piece usually employed is the Huy-
genian, or negative eye-piece (Fig. 4). This is composed
of two plano-convex lenses, with their plane sides next
the eye. Their focal lengths are as 1 to 3, and their
distance apart half the sum of their focal distances.
Several of these, having different magnifying powers, are
supplied with good microscopes. It is best to use a weak
eye-piece, increasing the power of the instrument by
stronger objectives when necessary. Kellner's eye-piece
has the lens next the eye made achromatic. The peri-
scopic eye-piece of some of the German opticians has both
lenses double convex. This gives a larger field of view
with some loss of accurate definition. For high powers,
I have used a strong meniscus in place of the lower lens
in the Huygehian eye-piece. Dr. Eoyston Pigott has
suggested improvements in eye-pieces by using an inter-
mediate Huygenian combination, reversed, between the
objective and ordinary eye-piece. This gains power, but
somewhat sacrifices definition. Still better, he has pro-
posed an aplanatic combination, consisting of a pair of
slightly overcorrected achromatic lenses, mounted mid-
way between a low eye-piece and the objective. This
has a separating adjustment so as to traverse two or
three inches. The focal length of the combination varies
from one and a half to three-fourths of an inch. The
future improvement of the microscope must be looked for
in this direction, since opticians seem to have approached
the limit of perfection in high power objectives, some of
which have been made equivalent to g'oth or T J th of an
inch focal length. As an amplifier, I have used a double
concave lens of an inch in diameter and a virtual focus of
one and a half inches between the object-glass and the
eye : piece. If the object-glass be a good one, this will
permit the use of a very strong eye-piece with little loss
of defining power, and greatly increase the apparent size
of the object.
THE MICROSCOPE. 27
Mechanical Arrangements. The German and French
opticians devote their attention chiefly to the excellence
of their glasses, while the mechanical part of their instru-
ments is quite simple, not to say clumsy. They seem to
proceed on the principle that as little as possible should be
done by mechanism, which may be performed by the hand.
It is different with English and American makers, some
of whose instruments are the very perfection of mechan-
ical skill. The disparity in cost, however, for instruments
of equal optical power is quite considerable.
Certain mechanical contrivances are essential to every
good instrument. The German and French stands are
usually vertical, but it is an advantage to have one which
can be inclined in any position from vertical to horizontal.
There should be steady and accurate, coarse and fine ad-
justments for focussing ; a large and firm stage with ledge,
etc., and with traversing motions, so as to follow an object
quickly, or readily bring it into the field of view ; also a
concave and plane mirror with universal joints, capable
of being brought nearer or farther from the stage, or of
being turned aside for oblique illumination. Steadiness,
or freedom from vibration, is of the utmost importance in
the construction, since every unequal vibration will be
magnified by the optical power of the instrument.
Among so many excellent opticians it would be impos-
sible to give a complete list of names whose workmanship
is wholly reliable, yet among the foremost may be men-
tioned Tolles, of Boston ; Wales, of Fort Lee, N.J.', Gru-
now, of New York ; and Zentmayer, of Philadelphia ;
Powell & Leland, Ross and Smith, Beck & Beck, of London ;
Hartnack and Cachet, of Paris ; Merz, of Munich ; and