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MICROSCOPY

BIOLOGY.

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A TEXT BOOK

FOR THE USE OF STUDENTS IN

HIGH SCHOOLS, NORMAL SCHOOLS AND
ACADEMIES,

> eel SD ree S9eN2Z/uK

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ALBERT SCHNEIDER, M. D.

‘¢ Valeat quantum valere potest.”

FAIRBURY, ILL.,
THE BLADE PRINTING Cicnce.

TO

CLIFTON SCOTT, B. 8., M. D.,

INSTRUCUOR OF NATURAL SCIENCES IN THE NORTHERN
ILLINOIS NORMAL SCHOOL.

THIS WORK IS DEDICATED,
IN ADMIRATION OF

His ABILITIES AS TEACHER AND IN REMEMBRANCE
oF MAny AcTsS OF KINDNESS SHOWN TO THE
AUTHOR WHILE A PUPIL UNDER
HIs GUIDANCE.

Entered according to Act of Congress, in the year 1891, by
ALBERT SCHNEIDER, M. D.,
In the Office of the Librarian of Congress, at Washington.

ah nn i a

This work is intended to acquaint the student with the
elements of Microscopy and Biology. It is not complete in

any of its parts. It is presented for the purpose of meeting

a demand in our more elementary institutions of learning,

and to create a desire in the student to investigate Nature

and its Laws for himself. The course of study as laid down
in our public schools, normal schools and academies is such
that one can not become a master in the field of biology.
Those who do not have unlimited time and a well lined purse
to carry on scientific investigations, can only hope to acquaint
themselves with the rudiments and first principles as present-
ed in this little work. Afterward, if desirable, they can con-
tinue in some first-class college or investigate for themselves.

The student before entering upon this'work is supposed
to have mastered the elements of chemistry and physics,
and also geometry and trigonometry. The laboratory work
is so arranged as to save both time and extra labor.

Microscopy.—Here are presented the construction and
uses of the simple and compound microscopes, the formation
of images and the refraction by lenses, etc. Some hints on
the purchasing and care of a good microscope. Much could
have been added which would however only have been tire-
some to the beginner. |

Biology.—A brief introduction gives the student some
idea of the extent of this field of investigation, but he should

not allow this to discourage him. The different steps are so
arranged as to make clear to the student what he is expected
todo. He is earnestly advised not to rely too much on the
outline, but to investigate and reason for himself the ‘‘ why”
and ‘‘ wherefore” of every step he takes.

There is a purpose in the arrangement of this work.
The various steps are not placed as if by chance. Therefore
the student should not omit anything.

The author will feel amply repaid if he has siavd in
- creating in his fellow student a love for the study of Biology.

A. SCHNEIDER.
Drxon, Aug. 30, 1890.

4

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ERRATA.

For ‘‘phylosophy” read ‘‘philosophy”’.

.For ‘‘refractoin” read ‘‘refraction”.

. Fig. 6, top a’ should be a.

.In Article 38, Proportion 5, introduce +1HG.
.For ‘‘triblet” read ‘‘triplet”.

.For ‘‘trible” read ‘‘triple”.

.For ‘‘trible” read ‘‘triple”.

.For ‘‘miccometer” read ‘‘micrometer’’.

.For ‘“‘olear” read ‘‘clear”. :

.For ‘‘evist” read ‘‘exist’’.

.For ‘‘Denterostomata” read ‘‘Deuterostomata”.
.For ‘‘mowers” read ‘‘mouers”.

.For ‘‘animal” read ‘‘vegetable”.

.For “mubticellular read “multicellular”.
.For ‘‘chitnous” read ‘‘chitinous”’.

.For ‘‘No. 2 SO,” read ‘‘Na,SO,”.

.For ‘‘Potasium” read ‘‘Potassium”.

..For ‘‘Tartarate” read ‘‘Tartrate”’.

MICROSCOPY.

(1) MICROSCOPES.-—(Gr., mekros, small; and skopem, to

view. )

Objects which are too small to be seen by the naked eye
are brought into view by an iastrument called a microscope.
The simple microscope was the first to come into use. A
simple microscope consists of a single lens or a system of
lenses by means of which the object is viewed directly. The
time and manner of its discovery is not definitely known.
There is no doubt:that the ancients were acquainted with its
use. Ptolemy in his ‘‘Optics’’ gave a table of the refractive
indices for glass and his results agree quite closely with those
of to-day.

The discovery of the microscope may have been by acci-
dent or by design. It is known that Jacharias Jansen & Son
constructed microscopes as early as 1590. In the year 1685,
Stellati gave a minute description of the bee which he could
only have done with the aid of the microscope. By its means
Leeuwenhoek made his wonderful discoveries. In 1673 he
discovered red globules in blood. In 1677 he discovered in-
fusoria in stagnant water. His microscopes were so con-
structed that he required a new one for every two or three
objects.

From the time of Jacharias Jansen till the construction
of corrected lenses many forms of microscopes were pro-
duced by scientists and opticians of Italy, France, Germany
and England. ‘They used only one kind of glass in the man-
ufacture of their lenses. The holders for these lenses were
of all descriptions and forms. The great hindrance to the
perfection of the simple microscope was spherical and chro-
matic aberration. About 1815 Wollaston and Frauenhofer

6 . MICROSCOPY.

gave their attention to the improvement of these defects.
They used two kinds of glass having different refractive in-
dices, namely crown and flint glass. Euler made an achro-
matic objective in 1776. When the greatest magnifying
power of the simple microscope, consistent with the greatest
possible correction for spherical and chromatic aberration
had been obtained, it was believed by scientists and opticians |
that the climax in microscopy had been reached. ‘Even after
the invention of the compound microscope such men as Wol-
laston and Biot predicted that the simple microscope could
not be excelled by the compound. It is not definitely known
when the first compound microscope was made. It could
certainly not have taken an optician long to comprehend the
necessary principles for the construction of .the compound
microscope after fully understanding the simple. In the an-
cient and middle ages scientists were more interested in
astronomy than in biology, whence it came that the telescope
preceded the microscope. The principles of construction are
very much the same in the two.

In the compound microscope we have a lest or a combi-
nation of lenses acting as one lens, forming a real image ;
this image is further magnified by a second lens or system of
lenses. In the simplest form only two lenses are necessary ;
one to form the real image, the second to further magnify
the real image. We could have an indefinite number of sys-
tems of lenses, each succeeding one magnifying the preced-
ing real image. By placing the eye in the focus of the up-
permost system we would see a virtual image of all the sev-
eral real images The reason why we do not use more than
two systems is because the image would appear indistinct on
account of too much light being absorbed in passing through
so many lenses. |

Only a few years ago microscopes and works. treating on
microscopy could only be bought by the wealthy, but now
the wonderful mechanical aids of to-day and the large num-
ber of dealers in microscopical material has made them com-
paratively cheap. Rapid strides are being made in the im-

MICROSCOPY. 7

provement of the microscope. Fifty years ago no one would
have dreamed of the improvements of to-day, and it is to be
hoped that fifty years hence the microscope of to-day will be
a thing of the past, for there is nothing seemingly so perfect
but it may be made more perfect.

(2) PHYSICS.—(G7r., physike; L., physica, natural phylos-
| ophy.)

Nearly every person with good eyesight can look down
the tube of a microscope and view an object which, of course,
has first been prepared and placed on the stage by an expert,
but very few know how that image is formed and brought to
the eye greatly magnified. Some of the laws of optics with
demonstrations are introduced here that the student may get
a more thorough understanding of the subject than he would
from the ordinary high schoo! text-book on philosophy. It is
true one may become quite skilled in the manipulation of the
microscope and not know anything about optics. Yet for his
own benefit and in order that he may be able to satisfy in-
quisitive semi-scientists he should acquaint himself as far as
possible with the mechanics and mathematics of lenses and
mirrors. 3

(3) IMAGES.—(Z., tmitarz, to imitate.)

An optical image consists of a collection of focal points,
from which light either really or apparently radiates. When
we see rays collected from real focal points we have a real
image. When we see rays collected from apparent focal
points we have an apparent or virtual image.

(4) A real image can be projected upon a screen, a vir-
tual image can not.

(5) The apparent focal point can exist only as long as
perceived by the eye. The real focal point can exist indepen-
dent of the eye.

(6) Rays diverging before reflection will diverge at the
same angle after reflection.

8 = | MICROSCOPY.

(7) ays converging before reflection will converge at
the same angle after reflection.

(8) Rays parallell before reflection are parallell after
reflection.

(9) Images formed by plane or. convex mirrors are al-
ways virtual. Those formed by concave mirrors may be
either.

(10) The general effect of a concave mirror is to pro-
duce convergency of rays.

(11) The general effect of a convex mirror is to produce
divergency of rays.

Fi, t.

APPARENT OR VIRTUAL IMAGE FORMED BY A PLANE MIRROR.

(L., mirare, to wonder.)

(12) Let m n in fig. 1 represent a plane mirror and
A B an object before it. Let the objects position be such
that the reflected rays will enter the eye at H. From A and
B let fall perpendiculars on the mirror, produce them till
aK= AEKand bG=BG. Now rays from A will Seem |
to radiate from the apparent focus a., and all those from Bb at
b., and all intermediate points between A and B will seem to ~
focus at similar points between a. and b. ‘Therefore the ob-
ject and image are equally distant from the mirror.

MICROSCOPY. 9

A C and ac are equal because they are two perpendic-
ulars between two parallel lines, BG =bGandAEK=a
EK, therefore by substitution and subtraction B C = b ¢; the
angles A C B and ac b are equal because they are both
right angles, hence A B =a b and B A C=b ao; that
is, the image by a plane mirror is equal in size, equidistant
and equally inclined with the object.

(13) Changing the position of the eye does not change
the position of the image by a plane mirror.

Rhigu 2.

CONJUGATE FOCI.

(14) When rays which radiate from a point are reflect-
ed by a concave or convex mirror they are again brought to
a real or apparent point. These points are interchangable
and are called conjugate foci.

If the radius of the mirror and the distance of one focus
are given the distance of the other focus may be determined.

(15) In fig. 2, let radius of mirror = r; the distance of
one focus A E = m, and the other focal distance a E = n.

The angle AB a is bisected by C B. Therefore A B
>aB::AC:aQC, butsince B Eis very small, AE: aE::
AC:aC. Substituting,

HO. MICROSCOPY.
fas) Pumas: Sn’: : Se ee
(2) mr—m n=m n—nr.
(3) mr—2 mn>— OT; or, —m r+ 2 mn

(4) 2m n—m r=nr; or, m (2 n—r)=nr.

nr
ee

(5) m= 5

(6) n=5—— Q. E. D.

V/ Fig. 3S.

Pk
IMAGE BY A CONCAVE MIRROR.

(16) Ina concave mirror when the object is placed be-_
tween the center of curvature and the principal focus the
image is real, inverted and enlarged. 1tis real because the
image can be projected on a screen. It is inverted because
the axes cross between the conjugate foci. It is eularged
since it subtends the angle of the axes at a greater distance
than the object. db bisectsabe,...ad:‘de::abi be
As b c is greater than b aso is dc greaterthanad. ad and
d ec measure the distances of object and image from the cen-
cer of curvature. |

Note.—Other problems in eoncave and convex mirrors
should be assigned for demonstration.

MICROSCOPY. il
LENSES.—(Z., lens, a lentil.)

(17) A lens is a transparent medium having at least one
curved surface. The most common forms are six in number
shown in fig. 4.

Fig. 4.

A Pe OD E F

(18) A, A double convex lens has a common base and
two equally or unequally convex surfaces.

(19) B, A plano-convex lens has one side convex, the
other plane. It is simply a segment of a sphere or half of
a double convex lens.

(20) ©, The meniscus or convexo-concave lens has one
surface concave, the other convex. ‘The convexity exceeding
the concavity.

(21) A, B and C have the general effect of double con-
vex lenses.

(22) D, A double concave lens has two equally or un-
equally curved surfaces.

(23) E, The plano-concave lens one surface plane the
other concave.

(24) F, The concavo-convex lens has one surface con-
vex, the other concave, the concavity exceeding the convexity.

(25) D, E and F have the general effect of double con-
cave lenses.

Note.—It is supposed that the sialon understands the
general effect upon light on passing through the various
lenses.

(26) Lenses of to-day are nearly all made of crown and
flint glass. Crown and flint have different refractive indices
and are used in order to correct spherical and chromatic aber-
ration as will be explained further on.

12 MICROSCOPY.
REFRACTION.—(Z., ve, back, and frangere, to break.)

(27) Refraction is the change in direction that a ray of
light undergoes in passing from one medium into another. —

(28) The angles of incidence and refraction are on op-
posite sides to the perpendicular of the surface.

(29) In the same media the ratio of the angles of inci-
dence and refractoin are the same for all inclinations of the
ray. :

Fig. 5.

(30) In fig. 5 A C is refracted to E and a C to e, so that
AD:EF::ad:ef, then by inversion EF .AD::e8#:
a d.

(31) This constant ratio is called the index of refraction.
It is found by dividing the sine of the angle of incidence by
the sine of the angle of refraction.

Let i = index of refraction. Then i BES

sine F E

(32) When the ray of light passes from air or some
other medium into the substance it gives the comparative
index.

MICROSCOPY. 13

When the ray of light passes from a vacuum into the sub-
stance it gives the absolute index.

(33) The following table gives the absolute indices of
refraction :

MCINIEE e. . 245 | Crown Glass (mean)......... 153

Carbon Disulphide .......... PG OME eee Meee eS io Sasha 1.37

SS SE rs Peery Pa BEE ee ale Cae talk choice goto a 1.34

iset Glass (mean) .........- 1.6 MGCR teen wee na eA Si) ere. ie
0S Soe Te GS Sak ba 22 TS A en Sra eth et eet 1.000294

mete esalSaM 2... 1.54° —Olmstead’s Philosophy.

REFRACTION BY A MEDIUM HAVING PLANE PARALLEL SURFACES.

(34) Substituting in article (31).
. ginea
1) i=———|,
sine ¢
(2) sine a =1 sine a!

1 eae
Also (3) sine a'= ——sine al

(2) x = (3)=(4) sine a=sine a" .:. the ray S and $'
are parallel, that is the incident and emergent rays by a refrac-
tive medium having parallel plane surfaces will be parallel.

14 MICROSCOPY.

Fig. Te Ba

jal

REFRACTION BY A MEDIUM BOUNDED BY INCLINED PLANES.

(35) A transparent medium bounded by inclined planes
is called a prism. The angle included by the planes is called
the refracting angle and the planes are called deviating
planes.

(36) The total deviation by a prism is equal to the sum
of the angles of incidence and emergence diminished by the
refracting angle. -

(37) .In fig. 7 let A B = the incident ray and @ Gi
the emergent ray. G DH will equal total deviation.

i) GDH=DBC+DCB.

(2) i—f@=é—el

3) GDH=(@—D+6—)=-4—

@ +e)
Because of the perpendiculars at B and C, C K y and K
B r are similar right angled triangles, therefore p = r.

also (4) p=r+e

hence (5) .i' + e =r.
SnbunG)y=(6) 'GD HW = 1-460 rae,

MICROSCOPY. 15
Fig. 8.

TO FIND OPTIC CENTER OF CONVEX LENS.

(37) The incident and emergent rays which enter and
leave a lens at the points of contact of two parallel tangents
will be parallel according to Article 34. The point where
such a ray cuts the axis of the lens is called the optic center.
It may become necessary to produce the axis.

In fig. 8, a and b are the points of contact of the parallel
tangent planes. The radii C a and C’ b being perpendicular
to these planes are parallel to each other.

Hence (1) Angieso and o' are equal.
And (2) Angles at P are equal.
Therefore (3) Triangles C a P and C' b P are similar.

Represent C' b, one radius, by r' and Ca the other radius
by r. Represent thickness of lens measured on the axis by t,

16 MICROSCOPY.

and distance from optic center to surface by e. From 1, 2

and 3 we get
(4) Oa Bes Si a.

Sub. (5) r’-—e:r—(t—e)isrir.

(6) ror—re=rr—("t—re=rr—r
f+ re.

(7) —vre —re= — rt.

(8). ere eer): = re

mt
(9) . e = ae
Fig. 9.

CONJUGATE FOCI.

(38) The relative distances of the conjugate foci can be
determined when the refractive index and radii are known.
Let x = refractive index and assume that the angles of inci
dence and refraction are so small that their ratios are the
same as the ratios of their sines.

Then (DG Fe Gil) 2 aes 2

By div. (2) K GI—IGH:1GH:.x—1:1.
Substituting (8) K GH: 1G H::x—1:1.

se (44)K HG:1H G::x—1:1.
(3) + ()=6) KG H- KG? DG Bia

Bat - (6) K GH+K HG=B K F=2K Rf +> hae

And) < (7). 1G H+ if GP. C=O 4 Lie
Therefore (8) K R F-+ K F R:1I C Ct+ 1 6 C::x—19 if

MICROSCOPY. 17

The angles at R, C, C’ and F are as the reciprocal of the
the distance from L., therefore substituting in (8) we have,—
1 1 1

Opptriiontop:s't

To Finp Principat Focws.

1 1
(39) In that case ie would equal; and let the
principal focus equal F then 9 in Art. 38 would equal :
1 1. 1 1
as me oT wee ho

Hence a eu

Formulae 9 and 2 may be applied to any form of lens.

To Finp THE Power or Any LEns.
(40) The reciprocal of the principal focal length of a
lens is called its power.
From 9 in Art. 38 we find,
1
eae er APT) form oy)
And 2 in a 39 equals

he 1
)—- = (x — l) (GT, + oy, ; therefore
1 1 1
oe RL oo
| Mace oR
(4) F ce Re a power of lens.
Fig. 10.

(41) To find the power of a combination equivalent to
a single lens :
Let a ray parallel to the axis - incident at R and § T be

18 MICROSCOPY.

the emergent ray. Draw RC paralleltoS T. A C will rep-

resent the focal length of a single lens having the same devi-- ~

ation as the above combination. A X is the focal length of
A. Leta represent the distance between the lenses. Then
BX =A X—a. I we regard T as one of the foci then
X must be the virtual conjugate of lens B corresponding to
T. Let f equal focal length of A and f* equal focal length of
i.) (Phew:

1
Oe |B Poa
Rub@y RX ake

; 1
Therefore (3) = Pee a a -
i 1 1
eae gh or

Pye ee ay 8
Pe Ee: OEY
From similar triangles AC R, BT Sand X A R, X B
S, we have,
(6)(BIvAC : BS :ARS BX ae
But A C equals F the focal distance of the combination.
Therefore (7) BT .F >: BS: A KR:: BX = ae
i ae B xX
Big a Ax
Pe A, | a

Sub. (10) ae ess a se Wael ii GE Ge

Girne

Gd tea seat
fit f— f—a 1
(11) 2 y F Sh

When the lenses are in contact a = o.
1 1 y :
(12) oe GSE, +r from which we get:

(42) The power of a combination of two lenses in con-
tact is equal to the sum of their respective powers.

The above formula can be applied to any number and
form of lenses.

Due attention must be paid to the signs of the powers.

MICROSCOPY. 19
IMAGES.—(Z., zmago, image.)

(43) Lenses form a great variety of images. Their size
and position depend on the kind of lens and position of the
object. If in a convex lens the object is placed between the
principal focus and the lens, the image will be virtual, erect and
enlarged. If the object is further from the lens than the prin-
cipal focus the image will be real, inverted and enlarged.
All real images are inverted. ,

In the compound microscope there are two kinds of im-
ages formed, one real, the other virtual.

Fig. 11.

20 MICROSCOPY.

(44) Fig. 11 shows the simplest form of the compound
microscope. ais the object glass or objective. The object -
is placed a little beyond the principal focus, when a real, in-
verted and enlarged image is formed at d, this real image is
further magnified by the eye piece A. This second image
is virtual and enlarged. The relative positions of the object-
ive and eye piece change the magnifying power. It is neces-
sary to form two ratios to find magnifying power of objective.
The diameter of the object is to the diameter of the image as
the distance of the object from the objective is to the distance
of the image from the objective, that is: b T:dT'::bx:d
x. A similar proportion may be formed for the eye piece :
ce:df::Ae:Af. The magnifying power of the object-
ive times the magnifying power of the ocular gives full mag-
nifying power.

PRACTICAL PROBLEMS.

(1) Ina prism the angle of incidence is 30° 41’, the
refracting angle is 25° 30°. What is the total deviating
angle ¢

(2) Find conjugate focus of a convex lens whose
radius is seven inches and whose refractive index is 1.6. One
focus being 3 feet from optic center.

(3) Find power of above lens.

(4) Find principal focus of a convex crown lens whose
radius is 12 in.

Note.—Teacher should assign some twénty similar prob-
lems.

MICROSCOPES.

Microscopes, as before stated, are of two kinds, simple
and compound. There are at present only a few important
forms of the first. These we will nowconsider. Theoretical-
ly the spherical lens will give the highest amplyfying power,
but it was soon found that as amplification increased, spheri-
cal and chromatic aberration increased also ; hence it became
impracticable to use the highest powers. These effects of ab-

MICROSCOPY. 21

erration increase toward the periphery. In the Coddington
lens which consists of a sphere of glass, this defect has been
partially corrected by cutting a deep groove around the mar-
gin and filling it up with some opaque material to cut off the
distorted marginal rays. ‘This lens focuses very near the ob-
ject. Fig. 12 represents a section of the Coddington lens.

Fig. 12.

The Stanhope magnifiers consist of a double convex ora
plano-convex lens. Itisso ground that the plane or least
convex surface is just in focus for the object. Good results
are obtained from this lens but itis less convenient than some
other form as the object must be fastened to the surface.
Both the Coddington and Stanhope magnifiers are in use yet,
but are rapidly making way for more convenient forms.

Sir David Brewster was the real inventor of the Cod-
dington lens It received its present name from a Mr. Carey
who constructed one for Mr. Coddington and supposed he
was the inventor. Fig. 13 shows a Stanhope lens.

ah cel Fig. 15.

Fig. 13.
Sas
| a Baas
|

Wollaston and Frauenhofer made partially corrected
doublets, that is two lenses in contact, one double convex of

22 MICROSCOPY.

crown, the other plano-concave of flint glass. John Brown-
ing constructed achromatic triblets which were very useful as
they focused at three times the distance that the Coddington
lenses did and hence made it easy to examine opaque objects.
Steinheil, a German optician, made similarly constructed
lenses which he termed ‘‘aplanatische loupen” (aplanatic
lenses) having a magnifying power of 5.5 to 24 diameters.
Figs. 14 and 15 show a doublet and a triplet.

COMPOUND MICROSCOPES.

Before attempting to do anything in microscopy the stu-
dent should have a thorough understanding of the mechani-
cal construction of the compound microscope. Under the guid-
ance of an instructor he should be shown the various parts
and their modes of operation. Skill in microscopy is only to
be obtained by diligent study and patient practice. Before
commencing any investigation the student should lay aside all
preconceived ideas and rely principally on his own observa-
tions, for ‘‘ things seen are not as things heard.” It is not
necessary that the beginner should have all the expensive ac-
cessories belonging to a microscope. They are sometimes
convenient and save time, but one having mechanical skill
and ingenuity can make contrivances for himself that will
answer the purpose very well.

We will now consider the parts of the compound micro-
scope and a few of the most important accessories. The first
thing to be considered is the stand. The office of the stand
is to hold the objectives and oculars in their respective posi-
tions. |

Stands are built on two models, Jackson and Ross. In
the Ross model the body is supported on a transverse arm,
this is again supported ou the summit of a racked stem which —
can be moved up and down by awheeland pinion. The body
itself is permanently fixed. In the Jackson model the body
has the rack-work attatched to it and is supported for a great-

MICROSCOPY. | 93

er part of its length on a solid base. Very few stands are
now made on the Ross model because it is less firm and dur-
able than the Jackson. The Ross stand leaves nothing to be
desired if well made. But taking it all in all the Jackson is
the best stand for either cheap or costly instruments,

The base or foot is that portion of the stand upon which
the other parts are supported. It should have three points of
support, never more, because three points will always rest
firmly no matter how uneven the surface may be. Some are
of a triangular or horse shoe shape. The one having the
three points of support is the best.

The second part of the stand is the pillar. It is fastened
to the foot and has upon its summit the joint or axis. There
may be one or two pillars. They should always be firm and
strongly made. |

The third part of the stand is the arm which is connected
to the pillar by the axis and supports some of the principal
parts of the instrument.

The fourth part of the stand is the body which. is the
tube portion working upon the arm by means of a rack and
pinion. It holds the objective, ocular and draw tube. The
tube is generally made of brass. Some are nickle plated and
all are black on the inside so as to prevent the reflection of
light. The standard length of the tube is six inches. The
lower end of the tube contains an extra piece called a nose-
piece into which the ‘‘Society Screw” is cut.

The ‘‘Society Screw” is so called because it was estab-
lished by the Royal Microscopical society of London, They
agreed that the threads on objectives should be cut of uniform
size and the screws should have equal diameter. All objec-
tive makers who have adopted the resolutions of the London
society can interchange their objectives and use them with
any stand. Never purchase an instrument that has not the
‘society screw.”

MICROSCOPY.
OBJECTIV ES.—(Z., 0b, against, and jacere, to throw.)

24

Before explaining the construction of objectives and
oculars we shall first consider chromatic and spherical aberra-
tion.

By chromatic aberration (Gr., chroma, color; and L.,
abberans, to deviate) we mean a separation of the prismatic
colors due to their difference in refrangibility. To produce a
distinct image all the colors must be together, hence we al-
ways have indistinctness accompanied with the separation
of the colors. Different substances have different dispersive
powers. This fact was discovered by Dolland, who thereby
removed a great obstacle to the perfection of optical instru-
ments.

Below we give the dispersive powers of a few substances
much used in optics:

ul mel ACAaASsia. a vic vue ose ,sae «f39. | Plate ‘Glass: . -... 335 .032
Plmmond Gul 7. be a ee 079 | HaiS Og... 2. 6.35) oe .031
lange lasses) = te ob Sehr ae 052: | Go He O......5 4.23 ee 029
EG See ers, sais Pe tones .043 | Rock Crystal... 026
WA NOME ake. wis ee Se a ee .038 | Blue Saphire. .. >...) 22333 .026
ROW il) AGteSS be. ote eck le ens 036°) Ga-Plo...: . 2... ee ee .022
—Olmstead.

We will suppose that two

prisms, one of crown and the

other of flint be so ground that the refracting angle will
separate the violet 5° from the red ray. In order to do this,
the crown prism whose dispersive power is .036 must refract

5 SS SIL 1
Teele ha AS
dispersive power is .052 must refract the ray 1°361; because

Sakae duahy eon
pea 1750.
Then the crown glass will refract the beam downward 2°19!
and the flint glass will refract it upward 1°36’. Now the dis-
persive powers of the two prisms acting in opposite directions
and with the same force (5*) will just neutralize each other.
The colors are therefore united and still the beam is refracted

downward (2°19*) — (1°35*) = 44",

the ray 2°19*, because The flint prism whose

Place these prisms together base to edge.

MICROSCOPY. 25

It can readily be seen how the same effect can be pro-
duced by means of lenses. A convex lens of crown glass
may produce a certain amount of dispersion ; this may be
neutralized by a concave lens of flint according to the ex-
planation given above.

In practice it is found that when the violet and red rays
are brought together, all intermediate points do not meet at .
exactly the same point, because the prismatic colors are not
separated by like intervals. Opticians usually correct those
rays which affect the eyesight most powerfully.

SPHERICAL ABERRATION.

Spherical aberration is due to the fact that the rays near
the margin are more refracted than those toward the axis.
The more nearly the lens approaches a sphere the greater will
be the spherical aberration. In earlier times and at present
in cheap lenses, this defect was corrected by means of a dia-
phragm which would cut off the distorted marginal rays.
Now the correction is made by using lenses of an elipsoidal
form or by using wider back lenses.

Fig. 16.

In fig. 16 a, represents the appearance of a ruled plate as
seen through an aplanatic lens, that is one free from spherical
aberration ; b, represents the same plate as seen through a non-
corrected convex lens, and c, as seen through a noncorrected
concave lens.

The objective is that part of the microscope which forms

26 MICROSCOPY.

the real image and is screwed into the lower end of the tube.
Objectives consist of a series of lenses ground to suitable
curvatures depending upon the desired magnifying power and
angular aperture. These lenses are held in place by the
mount. Objectives are generally spoken of in terms of their
amplification. The standard of comparison being the magni-
fying power of a single lens having the given focal length.

- For example, a one-fourth inch objective does not focus one-
fourth inch from the object but has the same magnifying
power that a single leus would have with a focal length of
one-fourth inch. The one-fourth inch may focus much nearer
than one-fourth of an inch, that depending upon the angular
aperture. The wider the angle the nearer it will focus to the
object. Objectives are spoken of as high and low powers. |
All below the one-fourth inch are called low powers, the
fourth inch and above are called high powers.

By aperture we mean the opening made by the extreme
marginal rays meeting at the focus. Much controversy exist-
ed in regard to aperture. Some claiming the high angles
were best and others favored low angles. Nearly all opticians
have come to the conclusion that it is always best to have the
highest possible angle. Aperture is either given in degrees
or its numerical value. Air angle may range from 10° to 175°
Some opticians have made lenses claiming to be ‘‘ infinitely
near 180°.” This seems almost impossible as some allow-
ance must be made for the thickness of the cover glass. The
student will readily understand that the wider the angle the
more rays will be utilized in forming the image, and hence
better definition and truer image. It is also plain that high
angles will focus very near the object and therefore allow but
little working distance and room for vertical illumination.
All objectives having a higher aperture than 175° must be
used as immersion objectives, that is some transparent liquid
must be placed between the object and objective having a
higher refractive index than air as water, oil, or balsam.
These liquids increase refraction and allow the objective to

MICROSCOPY. 27

focus farther from the object. The beginner should not get
the high angle objectives as they require delicate manipulation
and skill to do successful work.

Instead of giving a separate angular value for each of
the various immersion fluids, a comparative numerical value is
given in which the air angle is considered to be the standard.
The numerical aperture is found by multiplying the sine
(natural) of the semi-air angle by the refractive index of the
immersion fluid used.

Objectives are either made of a double or trible sys-
tem of lenses. Low powers and angles may be made of
a single system. Most triblets have a single front lens, a
double middle and atrible back lens. ‘‘Wenham’s Formula’’
is a trible combination having a flint concave of a trible mid-
dle to correct the aberration of the single anterior and pos-
terior crown lenses.

There are also separable and adjustable objectives in the
market. The student is advised not to buy or use them.

EYEPIECES OR OCULARS, (L., oculus, eye.) .

The eye piece slides into the upper end of the draw tube
and forms the virtual image. There are three kinds of ocu-
lars in use, the Huyghenian, solid and orthoscopic. The
most common variety is the Huyghenian so named after its
inventor who first used it with his telescope. It consists of a
small upper lens called the eye dens and a larger lower lens
called the field lens and diaphragm between, not midway, but
nearer the field lens in the ratio of 1: 3. They are some-
times called negative eye pieces because the convexity is
turned from the eye. High powers are termed ‘‘ deep”’ and
low powers ‘‘ shallow,” these terms refer to the curvature of
the lenses. Solid eye pieces were the invention of Mr. Tolles.
They are called solid because they consist of one solid piece
of glass on the ends of which the proper curvatures are
ground. A groove is cut into the glass at a proper distance

28 MICROSCOPY.

between the two ends and filled up with some opaque sub-
stance to answer for a diaphragm. They are used principally
with high powers. The orthoscopic ocular consists of a trible
eye lens and a singie field lens with no diaphragm. It is well
adapted for micrometer work.

Eye pieces are not made of the same size, hence the ocu-
lars of different makers can not be used with other micro-
scopes.

Oculars are generally named A, B, C, D etc., but the D
of one maker will not have the same amplification as the D
of another maker. American manufacturers name theirs like
the objectives, two inches, one inch, one-half inch, etc., ac-
cording to their magnifying power.

In selecting good objectives the following qualities are to
be considered :
(1) Working distance.
(2) Definition.
(3) Freedom from distortion.
(4) Penetrating power.
(5) Resolving power.

Working distance.— By working distance is meant the
distance between the object and lens when in focus. It de-
pends upon the aperture and magnifying power. Great work-
ing distance is valuable for dissecting purposes and the ex-
amination of opaque objects. But when an object has been
prepared and mounted for transmitted light there is no need
for more working distance than will admit of the use of see
cover glass.

Definition.— This is the most important property of ob-
jectives and should always be taken into consideration. It
depends on the absence of both forms of:aberration. An
objective that is achromatic and aplanatic will have perfect
definition. The image by such an objective will appear dis-
tinct to the very edge. There should be no discolorization or

MICROSCOPY. 29

distortion. Be sure to test an objective for definition before
buying. |

Freedom from distortion.— This depends on the correc-
tion for spherical aberration. Those whose field of vision
should be well defined under one focusing, margin as well as_
center. As a test object the ‘‘ Nobert band plate” is very
much used. It consists of a plate of glass with lines ruled
upon it ranging from 1,000 to 112,000 to the inch. The lines
_ should appear parallel and straight.

Penetrating power.— It is that property by virtue of
which several planes of an object may be seen at one focus-
ing. It depends on two things, accommodation depth of the
eye and depth of focus. These depend on the aperture and
amplification. The higher the power and aperture the less
penetration. For some reason the accomodating depth of the
eye does not decrease as rapidly as the depth of focus.

Great penetration is useful in examination of opaque ob-
jects and in the examination of transparent objects that can
not be cut thin.

Resolving power.— This is another very important prop-
erty and depends always wholly upon large aperture com-
bined of course with correction for sphericity and chromatism.
As a test the ‘‘ Nobert test plates” are used having lines
ruled on them ranging from 10,000 to 200,000 to the inch.
Mr. Meller has made what he calls a ‘“‘test platte” (test
plate) upon which he has mounted twenty diatoms having
striations ranging from 3,000 to 92,000 to the inch. The
better the resolving power the more of these lines can be seen
to every linear inch.

The draw tube is supplied with most monocular micro-
scopes. The draw tube slides into the tube, at the upper end
is a milled co//ar which acts as a stop. The eyepiece is fitted
into the upper end and by this means the draw tube becomes
an aid in increasing the magnifying power. Some of these

30 MICROSCOPY.

tubes are plain and others are divided into inches and parts
so that results may be noted.

Coarse adjustment is a contrivance for moving the body
back and forth quickly. It is done by means of a rack and
pinion, and sometimes by merely sliding the tube in an outer
sheath. The rack and pinion is far more preferable.

The jine adjustment is used after an approximate focus
has been obtained by the coarse adjustment. It is attained
by a fine thread acting upon the body directly or by means of
levers.

Both adjustments should be very sensitive. They should
have true fittings and gearings, anything to the contrary gives .
evidence of poor workmanship.

The stage is that part upon which the object is placed for
examination. It is attached to the arm and may be either |
fixed or revolving onan axis. The stage should be made very
hard and smooth. Glass stages are the best.

The mzrror is placed below the stage on the sliding and
swinging mirror bar so that it may be turned in any direction.
Mirrors are generally either plane or concave. Most all mir-
rors have two surfaces one plane the other curved. Experi-
ence and a knowledge of optics will give the best informa-
tion as to their proper use.

The diaphragm is a contrivance with which to regulate
the admission of light. They are of two kinds— wheel and
iris diaphragms. The wheel diaphragm consists of a disk
with holes of different sizes. The iris diaphragm consists of
a number of movable shutters. These are made to open and
close, similar to the human iris, by means of a thumb screw.
Diaphragms are either attached to the stage or sub-stage.
-The proper position for the opening is as near the slide as
possible.

The szb-stage is a ring below the stage to receive various

MICROSCOPY. 31

accessories. It is generally provided with an adjustment to
regulate its distance from the object. |

3 The bull’s eye condensor is a double or plano-convex
lens mounted on a stand for the purpose of concentrating
light upon an opaque object. Its use and manipulation de-
pends upon its construction.

The swb-stage condensor is attached to the sub-stage. It
cousists of a combination of lenses and is corrected for both
forms of aberration. It can only be used with satisfactiou
by advanced students.

Double and trible nose pieces are useful when itis desired
to quickly change objectives. They may be made to hold
objectives of different powers which can be swung in and out
of focus whenever desirable. Those holding three, four or
more objectives are generally too clumsy.

Microscope Tables —When two or more microscopists are
at work at the same time it is convenient to have a revolving
table as it saves a great deal of rising to change places in
observing. The table should have three supports and should
be well made. One that creaks and is loose at every joint is
worse than useless. The larger the table the more can con-
veniently work at the same time.

Microscope Lamps.—The best time to work is day time,
using the light.from a white cloud on a sunny day. Never
use direct suulight ; it is too bright. When it becomes neces-
sary to use artificial light an ordinary student lamp can be
used. To protect the eyes all superfluous light may be cut
off by ashade. To get the most intense light turn the edge
toward the object, but if quantity of light is required rather
than intensity the flat side may be used. The student should
be careful not to use too much light as it sooner or later ruins
the eye sight. Lamp light gives a very objectionable yellow

32 MICROSCOPY.

tint to objects; this may be corrected by colored glass.
Blue glass very effectively corrects this defect. The blue
glass used by chemists does very well.

Camera Lucida, (L., camera, an arched roof; and lucida,
bright.)—The student should always delineate objects under
examination. The image is thereby more firmly fixed in his
mind, besides it teaches him to observe more closely. He
will be surprised to find that he observes things which he
would not have noticed otherwise. The camera lucida and
neutral tint reflector are contrivances used with the micro-
scope in drawing images of objects under examination. The
student of average ability can construct the neutral tint re-
fiector for himself. Take an ordinary cover glass, incline it
45° to the eye lens of the ocular, so that the center of cover
glass and center of eye piece will coincide, fasten it in its
place by some contrivance. Now incline the tube of the mi-
croscope till it is at right angles to the pillar. The cover
glass will refract the image at right angles. The eye looking
down through the center of the cover glass will see the image
projected on a paper placed below on the table. The posi-
tion of the light and mirror must be changed to produce the
proper illumination. Be careful not to haye too much light
where you are going to draw. A prime object in drawing is
to produce exact representations. The student should use.
paper ruled into squares. Place a cover glass ruled in squares
on the diaphragm of the ocular; this projects the image of
the squares with the image of the object. By this means very
exact work can be done. Amplifications and reductions can
be made at will. Cut off most of the light from the paper on
which the image is projected, so that it will appear in clearer
outlines. Get a good, sharp lead pencil and trace the outline
of the image on the ruled paper. It is well to use a tinted
cover glass, as it gives a better defined image. The student
will be surprised to find what he can accomplish by this sim-
ple means.

The camera lucida consists of a prism, and is used in the
same manner as the tint reflector.

MICROSCOPY. 33

Miccometer, (Gr., nikros, small; and metron, measure).
_ This is a contrivance for measuring all microscopical objects.
In the present age of progress the metric system is coming
more and more into use; hence it is best to get those mi-
crometers ruled occording to that system. They are gener-
ally ruled to millimeters, tenths and hundredths. Our best
scientific works give all measurements in that system. The
stage micrometer is placed on the stage of the microscope,
just below the object slide. It can only be used directly with
_ low powers, as the object and micrometer must be in focus at
the same time. With high powers another method may be
employed. Make a drawing of the object by means of the
camera lucida. Now replace the object by the micrometer,
and draw its markings over the previous sketch. Simple
inspection will show the magnitude of the object.

Eye-piece micrometers slide into the ocular just over the
diaphragm. These micrometers must be corrected for diifer-
ent powers. The actual experience, directed by a teacher,
is best here.

Numerous other accessories could be mentioned, but the
beginner is advised to purchase only those that are absolutely
necessary, as they are generally very costly and are too much
of a strain on the purse. The beginner will also soon find, to
his sorrow, that he can not use them. Never buy anything
because it is cheap; rather because itis good. ‘The person
who buys a microscope, or anything else, because it is cheap
is the loser in every case. Some advice on the purchase of a
microscope might be in order :

1. Make up your mind as to what you want before you
make up your mind to buy.

2. Select a good, strong, Jackson stand in which all the
gearings work smoothly. It should always admit of the use
of the more important accessories.

3. Select good objectives, and test them before buying.
This is of special importance.

34 MICROSCOPY.

4. Select good oculars and test them.

5. Deal only with reliable firms. ) :

6. Take good care of your instrument. Do not let
every one handle it, especially those who know uothing
about microscopy.

A little advice on keeping a microscope might be in
order : ee

When through using the microscope seperate the various
parts as much as is necessary, and wipe them perfectly clean
and dry with a silk handkerchief or a piece of chamois skin.
Rub up and down, lengthwise, with a light, brisk movement.
When through wiping no finger marks should be seen any
where. Place the various parts in their proper places in the
microscope case. Do not throw half finished mounts, slides,
cover glasses, botanical specimens, etc., helter skelter into
the case. The microscope case was made for the microscope
only. After being certain that everything is in its proper
place, lock the case and put the key in your pocket or some
other place where you know it can be found when wanted.
Keep the microscope, or any other scientific instrument, in a
dry place, away from chemicals. |

CHAPTER IT.

miLOLOG Y.

Biology, (Gr. déos, life ; and logos, discourse.) or natural
history, is the science which treats of the organic world in its
various forms and relations. It includes the entire fields of
zoology and botany. The two are inseparably connected.
Scientists have so far been unable to draw the dividing line.

In all scientific investigations a systematic classification
and arrangement is necessary, not so much for the original
researcher, but that it can be properly presented and under-
stood by those who follow in the field of investigation. Biol-
ogy, as the word signifies, is a life discourse, and treats of the
composition and corelation of organic bodies ; it is, therefore,
distinct from mineralogy, which treats of minerals, or inor-
ganic substances. For convenience sake biology is divided
into zoology and botany.

Zoology is the science which treats of animated nature.
It can first be divided into structural zoology, which treats of
the organization of animals. Structural zoology is divided
into anatomy, which treats of the constitution and formation
of animal bodies; and physiology, which treats of the func-
tions of the organs of organized bodies in a healthy state.
Pathology treats of functions in an abnormal state. Anatomy
separates first into descriptive anatomy and histology. This
divides again into skeletology, which comprises osteology and
syndesmology; and sarcology, which comprises myology,
neurology, angiology, adenology, splanchnology, and derma-
tology. Secondly, anatomy separates into embryology, which
is the doctrine of embryonic development; and, thirdly,
morphology, which treats of the anatomical conformation of

36 BIOLOGY.

; e

parts. Homological anatomy treats of the relation of differ- »
ent parts in the same individual. Comparative anatomy
treats of the relation of like parts in different individuals.
Philosophical anatomy treats of or inquires into the mode or
model upon which the animal body is formed. Morbid anat-
omy treats of organic structure in adiseased state. Historical
zoology treats of the successive appearance and disappear-
ance of animals in the various ages. It is divided into geo-
logical zoology, which treats of animals now extinct, and
recent zoology, which treats of animals now living. Theoret-
ical zoology attempts to explain the possible origin of life and
species. Space will not permit the giving of a complete out-
line of biology.

The actions of living matter are called its functions.
These functions, though very numerous, may be resolved into
three kinds—(1) functions which effect the material composi-
tion of the body, and determine its mass, which is the balance
of the process of waste on the one hand, and assimilation on
the other; (2) the functions that subserve the process of
regeneration, which is nothing more nor less than a detach-
ment of a part having the power to develope into an inde-
pendent whole; (8) functions by virtue of which one organ
has the power to exert an influence upon other organs in the
same body, and thus become a mode of molar motion. The.
first may be termed sustentive, the second generative, and
the third correlative functions. The most complex body is
merely an aggregate of cells.

Among the more simple forms of animal life known to
biologists is the amceba, closely resembling a white blood
corpuscle, and consisting almost wholly of an undifferen-
tiated mass of protoplasm. Generally there are present
one or more nuclei, although these may be absent. This
simple organic structure possesses all the most important
fundamental vital properties found in the most complex
body known. (1) It is contractile. It can produce within
itself a change in form and position by what is so well

BIOLOGY. 37

known as the ‘‘amoeboid movement. (2) It is irritable, or
automatic. When it comes in contact with a foreign body
motion is the result. ‘This is not passive but active motion.
In fact, the ameeba is rarely at rest. (3) It is receptive and
assimilative. It has the power to take up and assimilate por-
tions of certain substances for food. (4) It is metabolic and
secretory. That is, the protoplasm undergoes a continual
change. The protoplasm now existing breaks up and is
removed, while a new protoplasm is formed from the food
taken up. (5) Itis respiratory. It takes in oxygen, which is
required in the oxidation of food, and gives out carbon diox-
ide, which is the result of oxidation. (6) It is reproductive.
The individual amoeba represents a unit; after a time this
unit divides into two separate units capable of again subdi-
viding.

Many eminent biologists have attempted to explain the
possible origin of life and species. Some theories have
been advanced, but none of them have yet been able to stand
alone. They fall to the ground as soon as their promulgat-
ors cease to support them. We might say that life is a series
of changes, both in structure and composition, wrought by
some intangible, incomprehensible force, such changes always
taking place without destroying the identity of the individual.
The most plausible theory, or rather, hypothesis, in regard to
the origin and development of species is that of evolution,
brought to its present perfection by Charles Darwin. He
defines it as a changing from the homogeneous to the hetero-
geneous, from the general to the special, from the simple to
the complex. It is, essentially, a process of differentiation, a
a method of progress from generalized types to those more
special and complex—a changing from a lower to a higher
individuality.

This hypothesis is by no means recent. It existed
among the ancient philosophers. An old cosmological
myth was that, at first, there existed a chaotic mass or
mundane egg, from which all things successively emerged.

38 BIOLOGY.

Thales taught that in the beginning every thing was in a fluid
state, from which some great, self-existing force formed all”
things. Anaxagaros taught that, at first, all consisted of
atoms, infinitely numerous and eternal, among which order
and arrangement was produced by a self-existing, intelligent
power or god. This was opposed by Democritus and Epi-
curus, who taught that chance, and not God, wrought, in infi-
nite time, out of numberless atoms, all existing things.

No student in biology can afford to jump at conclusions.
He must lay aside all preconceived ideas and notions, must
allow nothing to come in the way of sound judgment. Fore-
most among all the foundation upon which evidential know!l-
edge is to be placed, must stand every test brought to bear
against it; for, if the foundation is rotten, the superstructure
will fall to the ground, no matter how well it may be planned.

Not until the perfection of the compound microscope was
it possible to make any real progress in biology. By means
of it we have discovered the ultimate constituents of organ-
ized bodies, the cells, and have been enabled to study the
lower forms of the organic world, such as the alge and _ bac-
teria. In comparatively recent time eminent biologists
believed that cells and minute organisms could originate de
novo; but it has been conclusively shown that every living
cell sprang from a pre-existing cell. Of course, leaving out
of consideration the question as to where the original cell
or ovum came from.

The animal and vegetable world is composed principaily
of four elements: oxygen, hydrogen, nitrogen and carbon.
The first three are gases; the last, carbon, isasolid. Carbon
has the property of interchanging its combining power, which
accounts for the many carbon compounds found in nature.
The predominance of gaseous elements in the organic world
is supposed to account for its high degree of molecular mobil-
ity, and, according to Herbert Spencer, ‘that comparative

BIOLOGY. 39

readiness displayed by organic matter to undergo those
changes in the arrangement of parts which we cal! develop-
ment, and those transformations of motion which we call
functions.” The primary form into which the four elements
enter is the semi-fluid substance called protoplasm, which is
almost the sole constituent of the lower forms of animal life.
Combined in different forms, these elements enter into all the
compounds found in the animal and vegetable world.

In the entire organic world nothing is at rest. There is
a continual change and interchange of cells and cell sub-
stance ; this change always tends toward a higher individual-
ity. The time will come when the present genera and species
will make way for higher organizations, as much higher than
we are as we are higher than those who lived before the great
glacial epoch. We can only affirm that in judging the future
by the past. We have noted the steady progress of develop-
ment, and we have no cause to think that we are now at the
acme of all progressive development.

As has been stated. the biologist has so far been unable
to draw the dividing line between the animal and vegetable
kingdoms. It is very probable that the lowest forms of ani-
mal and vegetable life existed together. No doubt, the high-
est developed plant, as well as man, sprang from the same
primordial mass of protoplasm. Beginning with Haeck-
el’s moners, the two great kingdoms begin to separate, each
in its line, rising to a higher degree of development. These
two kingdoms developed because one was the supporter of
the other. What one discards the other uses. No third or
- fourth organic kingdom developed, because it was not needed.
In the future nature may be in demand of entirely different
organisms than we now find.

The beginner is advised not to study unknown forms of
life till he understands those which have been described.

40 BIOLOGY.

Below is given an outlined differentiation between the
lower typical forms of vegetable and animal life:

=

UNICELULAR PLANTS AND ANIMALS.

ANIMALS. PLANTS.
1’ Composition. 1' Composition.
1? Pretoplasm. | 1* Protoplasm.
OT ATAELS. 2” Starch.
1? Cell Wall. 3° Chlorophyll.
1° Albumen. 2' Parts.
2? Cell Contents. 1? Cell Wall.
' 1° Nitrogenous Substan- 1° Cellulose.
2° Nucleus. [ ces. 2? Cell Contents.
3' Assimilation. 1° Nitrogenous substan-
1° Endosmosis. 2° Starch. [ces.
i Water 3° Chlorcphyll.
2° Nitrogenous Substan- 4° Nucleus.
1* Albumen. |ces. 31 Assimilation.
2* Gelatine. 1’ Endosmosis.
2” Exosmosis. i* Water.
1° Carbon Dioxide. — 2° Carbon Dioxide.
4* Reproduction. 3° Ammonia.
1’ Division. 2” Exosmosis.
2° Budding. 1° Oxygen.
5' Form. 4' Reproduction.
1’ Irregular. i 1° Division.
6* Size. 2° Spore Formation.
1’ Microscopical. 5' Form. |
7’ Motion. 1° Spherical.
1° Generally in motion. 2” Oval.
3° Oblong.

In the animal kingdom, the 4’ Cylindrical.
paramecium may be taken as a 52 Wedge-shaped.
typical example for examination, 62 Linear.
and in vegetable kingdom some _ 6! Gjzoa.
of the numerous forms of des- 12 Microscopical.
midia.. 7 Motion.

1° Generally motionless.

BIOLOGY. 41

Before entering upon any kind of work see that you are
prepared and supplied with the necessary material for a be-
ginner in biology. Some of the reagents can be omitted oe

_ they are absolutely necessary.

MATERIAL FOR A BEGINNER.

1 Microscopes.
1° Compound Microscope.
1° Accessories.
1* Objectives.
1°? One inch.
2°? One-fourth inch.
2* Oculars.
1° A or one inch.
2° B or 4 inch.
3* Bull’s eye condensor
4* Neutral tint reflector
5* Camera Lucida.
6* Micrometers.
i? Stage.
2” Dissecting Microscope.
3° Simple Microscope.
1° Coddington Lens.
2° Stanhope Magnifiers.
1* Doublets.
2* Triblets.
3* Achromatic.
2 Dissecting case.
1” Dissecting knives.
2” Scissors.
3” Forceps.
1° Straight.
2° Curved.
4° Blow pipe.
5° Camel’s hair pencil.
6” Dissecting needles.
3' Microtome.
4' Turn table.
5' Slide Cexnterer.
6' Pipette.
7’ Alcohol lamp.

8’ Glass slides.
1’ Smooth edge.
2° Rough edge.
9* Cover glasses.
1’ Various sizes.
10° Labels.
11* Slide boxes.
12* Pencil drawing outfit.
13° Reagents. (See recipes.)
1* Hardening agents.
1° Alcohol. [solution.
2° Bichloride of mercury
3° Tannin solution.
a Chromic acid. [sium.
5° Bichromate of potas-
6° Osmic acid.
2” Softening agents.
1° Acetic acid.
2° Glycerine.
3° Potash.
4° Soda.
5° Ammonia.
6" Caustic soda.
7? Nitric acid.
3° ae drating agents.
1° Phosphorie acid.
2° Potassium carbonate.
3° Calcium Chloride.
4° Heat.
4° Bleaching agents.
1° Chlorinated soda.
2° Chloride of lime.
3° Chlorate of potassium.
4" Bichromate of potas-
5° Nitric acid. [sium.

AQ BIOLOGY.

6° Turpentine. 6° Staining fluids.
7* Chlorine. 1° Carmine.
5° Solvents. 2° Haemotoxylin.
1° Acids. 7” Mounting mediums.
le E Pe oer "3 _ 1 Balsam.
yaa Ta. ba & 2° Glycerine.
3* H OL. 3° Water.
7 an Od Oh 4° Dammar.
2° Alcohol. 5° Mastic.
3° Benzol. 8° Finishing agents.
4° Benzine. 1° Oxide of zinc.
5° Oil of Cloves. 2° Carmine.
6° Oil of Cajeput. 3° Ultramarine.
7? Chloroform. 4° Lamp black.
8° Ether. 5° Verdigris.
9° Petroleum. 6° Chrome yellow.
10° Water.

. Before one can do satisfactory work with the various
reagents their actions upon different tissues must be under-
stood.

Among the hardening agents alcohol is the best and most
used. It absorbs moisture very readily without destroying
the fresh appearance of the tissue. It must be remembered
that it dissolves gums and resins used in microscopical work.
Bichloride of mercury is a very efficient preparatory harden-
ing agent. It is supposed to act by forming insoluble albu-
minoid compounds. It must be borne in mind that it is a pow-
erful poison. Tannin is used for gelatinous substances. It is
used to inject blood vessels to prevent the passage of color-
ing matter through them. Weak solution of chromic acid
combined with the bichromate of potassium is a good harden-
ing agent for nervous tissues. Osmic acid in 1 per cent. so-
lution is much used for protoplasmic substances. It is very
poisonous.

Softening Agents.—Acetic acid diluted with about four
times its amount of water is much used. It renders tissues
quite transparent. It dissolves phosphate and carbonate of
lime. It can be combined with glycerine as a preservative
fluid. Glycerine is probably most used. It prevents the dry-

BIOLOGY. 43

ing up of tissues. The alkalies all have a similar action upon
most tissues. They are much used with vegetable tissues.
Nitric acid is sometimes used as a softening agent. It must
be borne in mind that it combines with metals of which the
instruments, etc., are made.

Dehydrating Agents.— These might have been given
with the hardening agents as water absorbers are also harden-
ing agents. Among the most important are anhydrous, phos
phoric acid, and concentrated sulphuric acid. The tissues are
not placed in contact with then but in a separate place under
a bell jar or some other air tight vessel. Potassium carbon-
ate and calcium chloride are used in a similar manner. Dry
heat is much used for different purposes, such as drying
specimens for mounting and driving air bubbles from under
cover glasses. |

Bleaching Agents.— Chlorinated soda and chloride of
lime are much used in bleaching vegetable tissues, also chlor-
ine. How to generate chlorine will be explained in another
chapter. Always eliminate all traces of these reagents after
the tissue is sufficiently bleached. This may be done by
means of a solution of sulphite of soda, 15 grains to the
ounce of water. ‘Turpentine is used to remove the intensity
of color from insect skeleton. Turpentine dissolves many of
the varnishes and finishing agents used in mounting.

Solvents.-_The strongest solvents are the acids. A
knowledge of chemistry will indicate when and where to use
them.

‘The alkalies will dissolve oils and fat, forming a soap.
Alcohol dissolves resinous substances. Benzo] and benzine
dissolve iodine, fat, gum, resins, rubber, etc. Turpentine,
ether and chloroform are good solvents for fats and most
resins. Water is the best universal solvent. Plenty of it
should be used. The object of solvents is to remove foreign
matter. Cleanliness is very desirable in microscopical work.

44 BIOLOGY.

Staining Fluids.— Carmine is best adapted for animal
tissue while logwood is best for vegetable tissue. It is best
to buy the fluids ready prepared. All dealers in micro-
scopical instruments keepthem. There are many other stain-
ing fluids, but those two mentioned are the only ones neces-
sary for the beginner.

Mounting Mediums.— Pure Canada balsam is the best
and most used. Dammar and mastic are also much used.
Care is necessary in using glycerine. Water is only used for
temporary mounts. Be

Finishing Agents.— Oxide of zinc is used to protect the
edges of the cover glass.

Carmine, ultramarine, lamp black, virdigris, etc., are
used with some vehicle in making colored rings. (See
receipes. )

STARCH. (0, Hy O;.)

The examination cf starches and pollen is introduced
here because they are easily obtained and will enable the
beginner to become somewhat accustomed to the manipula-—
tion of the microscope, at the same time affording useful in-
formation.

Starch is one of the most important carbohydrates. It
is very abundantly diffused throughout the vegetable king-
dom. There is no plant in which it cannot be found during
some stage of its existence. When purified it is a white,
glistening powder which gives rise to a crackling sensation
when rubbed between between the fingers. It consists of
firm, minute granules, varying in size and shape. LEach
granule consists of a series of layers deposed upon each other
causing the appearance of concentric markings. These
markings are arranged around a point which is generally ec-
centric in position called the hilum. The appearance of the
concentric rings are due to the fact that the various layers are

BIOLOGY. 45

alternately harder and softer in comparison with each other
which produces a difference in refractive power and hence
the striations. | |

Make temporary mounts and examine first with low
power and then with the 4-inch objective.

STARCHES. — LABORATORY Work.

1’ Potato starch.
1’ Hilum.
2” Concentric rings.
3° Shape.
1° Irregular pear shaped.
_# Size.
1° From 2.5 to 62.5 m. m. m. in diameter.
2° Comparative sive.
5° Admit a drop of solution of iodine under cover glass.
1° Note result and explain.
2* Wheat starch.
1° Hilum.
1° Round or transverse.
2” Concentric rings not distinct.
3” Shape.
1’ Disc like, flattened.
4” Size.
1° 2.5 to 35. m. m. m. in diameter.
2° Comparative size.
5” Admit a drop of solution of iodine.
1’ Note result.
3' Oat starch. (See 1' and 2’).
4’ Corn Starch. (See 1’ and 2’).

(a) Boil some starch with diluted sulphuric acid (H, S O,).
This process will convert it into a substance having the same
chemical composition as starch but turns the plane of polar-
ization to the right, hence it is called dextrine. (L., dextra,
right, to the right.) By continuing the boiling dextrine is con-
verted into sugar.

46 BIOLOGY.

(b) Carefulty heat some starch in about 120 parts of
water. The cellulose, which is insoluble, wili settle to the
bottom as a turbid deposit while the granulose form a per-
fectly olear solution.

(c) Iodine test for starch.

(1) Heat some starch solution, add solution of iodine,
no visible actions takes place. Allow it to cool and note re-
sults.

(2) Iodine must be in a free state. Solutions of iodine
salts will not do.

(3) The presence of a third organic substance will
generally interfere with the test.

POLLEN.— (L., pollen, a fine flour.)

Pollen is that part of the flower which develops the ger-
minating power of the ovule.

The student is supposed to be sufficiently acquainted with
botany to understand the growth and development of plants.

The stamens are simply modified leaves. The filament
represents the stem of the leaf, while the anther represents
the blade or leaf proper. The epidermis of the anthers is
very much like that of the leaves only that it contains no
stomata and generally no chlorophyll. The anthers or spore
cases have a homogeneous parenchyma whose cells are close-
ly crowded. After a time new cells develop within the case
and rapidly multiply. These form the pollen. The sun’s
heat causes the pollen case to break open when the pollen
escapes as a very fine powder and falls upon the stigma.

We shail now describe a pollen grain more closely. It
is simply a cell consisting of a cell wall and cell contents.
The external cell wall or extine is what gives the pollen its
form and color. All the many beautiful markings of the
pollen which are always constant in the same species, are
due to the extine. Hence from the examination of the pollen

BIOLOGY. 47

we may name the flower to which it belongs. “The extine is
formed out of a secretion from the internal coat or intinue
which directly envelops the viscid, protoplasmic, fertilizing
fluid.

The manner in which the pollen reaches the ovule is very
interesting. It is weil known that the stigma is continually
covered with moisture. When the anther bursts open the
comparatively dry polen grain falls upon the stigma and
is retained there by the thin viscid fluid. Osmosis takes
place ; the more thin fluid of the stigma passes into the pol-
len and also causes the hard, brittle extine to burst open at
the surface which is in contact with the stigma. This allows
the extensible intine to protrude. Osmotic action contiuues
between the pollen and those cells of the stigma which are in
immediate proximity. On account of the greater viscidity of
the pollen fiuid it gains more by endosmosis than it loses by
exosmosis. ‘This causes the stigma cells to shrink and create
a space for the passage of the extended pollen membrane
which we will now call the pollen tube. The reason that the
intine does not simply expand on the surface of the stigma is
because of the weight and resistance offered by the hard
extine, and some directive influence not mentioned.

The intine continues to grow and extend downward by
the above described process till it reaches the ovule. It is
yet a question of doubt whether the pollen tube enters the
ovule or whether it simply comes in contact with it and the
fertilizing fluid passes into the ovule by osmotic action.

PotLen.— Laporatory Work.

Select the pollen of some species of flower. That of the
hedge bind weed is a good example to start with on account
of its size and simple form.

Place some pollen dust on a clean slide and cover with
cover glass. Examine first with low power then with the
+-inch obj. and B ocular.

48 BIOLOGY.

1* Form. ‘Note carefully.
2' Size. Measure carefully. ;
3° Parts.

1’ Extine.

1’ Markings. Note carefully. Make drawings on
good paper and keep for future reference and comparison.
2° Color.

2” Intine. Press slightly on cover glass. This will rup-
ture the extine and allow the intine to protrude. Note its
extensibility and comparative toughness.

3° Fertilizing fluid.

1’ Composition.
1* Fat. Smash some pollen on a piece of paper.
It will leave grease spots.
2* Starch. Admit some solution of iodine under
cover glass and note results.

Carefully examine twenty species of pollen in your vicin-
ity before proceeding to the next.

FERMENTATION.—(L., ferveo, I boil.) — ,

Fermentation is a species of metabolic change in organic
substances developed and maintained by the life action of
low forms of micro-organisms called the germs of fermenta-
tion, each fermentation caused by its peculiar germs. In fact,
in noticing the similarity between fermentation and infectious
diseases it was believed that the latter also are forms of fer-
mentation. Henle, in 1840, expressed the belief that living
organisms, probably of vegetable origin, were the cause of
acute specific diseases. Bassi and Audouin, in 1838, had dis-
covered the fungous nature of the muscardine disease in silk
worms. In 1836, Schwan found that fermentation was caused
by living cells apparently of vegetable origin. These investi-
gations and discoveries led to two theories as to the cause of
fermentation—Ist, the germ theory, and 2d, the physical
theory. The germ theory, which is now accepted by the ma-

BIOLOGY. 49

jority of the scientific world, was first introduced by Astier,
Schwan and Cagniard, and brought to its perfection by Pas-
teur. It gives for the cause of all fermentations a micro-
scopic germ. Alcoholic fermentation is taken as the typical
example. It is caused by the sacharomyces or torula cere-
visiae, a living organism which is always found where alco-
holic fermentation takes place. These organisms are unicel-
lular, multiplying by division. They require for their food
sugar and nitrogen. ‘Thechief products of their life action
are alcohol and carbon dioxide. The germ theory, during its
infancy had powerful opponents. The principal ones were
the believers in the physical theory and the advocates of
spontaneous generation. The physical theory, started by
Willis and perfected by Baron Liebig, teaches that fermenta-
tion is due to peculiar molecular action, that is the molecules
underwent motor decay. This molecular motion was capable
of being transmitted to other unstable organic compounds.
This action was called ‘‘ catalysis”? or *‘ catalytic”’ action.
(Gr., kata, downwards; and /yo,’I dissolve.) The physical
theorist could not explain why the first molecule underwent
motor decay any more than the germ theorist could explain
the origin of the original organism or germ. Hence it is seen
that Liebig and his followers accounted for fermentation with-
ont the intervention of bacteria. They acknowledged the
presence of germs, but explained their presence by saying
they were the result and not the cause of fermentation.
Spontaneous generation was strongly advocated by the physi-
cal theorists. Bastian affirmed that organic substances, hav-
ing undergone molecular decay, will cause the origin de nowo
of certain fungi. The germ is present because the change
wrought in the substance has made it the proper food for the
germs to feed upon. -A very simple experiment will show the
fallacy of spontaneous generation. Take two flasks, both
filled with organic substances capable of undergoing fermen-
tation. Sterilize both-by boiling so that there is a certainty
that no living germs or spores are present, and hermetically
seal one flask by means of the blowpipe. Let the other re-

50 BIOLOGY.

main open. After a time the open flask will contain numer-
ous living organisms while the sealed flask will show no signs
of life.

Both theories have good arguments pro and con, but the
germ theory has by far the greater claims for being the true
theory. (1) Under no circumstances will fermentation take
place without the presence of germs. (2) A given species
of germ will always produce acertain kind of fermentation.
(8) Introducing germs into a sterile substance will at once
develop the process of fermentation. (4) Culture fluids have
been made in which it could be demonstrated that none but

a given species of germs were present. Such a culture —

fluid always caused its peculiar kind of fermentation.

LIFE._(A.-8., Uf)

The great problem of life is as dificult of comprehension
as itis important. What is lite? There is no definition that
is unassailable. The truth of this no one more fully realizes
than the scientist. Our knowledge of life is too meager and
the data from which to form conclusions are too few to give
us a real conception of the relations of living substance
to its surroundings. The definition given in the intro-
duction to Biology is by no means perfect, nor is the
one I am about to give. We might say that life is that
relation of force to matter which produces a substance
capable of a cyclical change. By this cyclical change is
meant birth, growth, reproduction and death. These
changes we observe in all living substances. The concep-
tion of the first change is almost axiomatic. We can not
conceive of a living substance without its being brought into
existence. The idea of growth is closely related. Birth
itself implies growth. The consideration of reprodnction and
death is more puzzling. It might be asked why does a living
substance after a certain stage of development reproduce its
kind and then die? Why does not the original living sub-

BIOLOGY. dL

stance continue to evist without reproducing? It would es-
sentially bring about the same final results. In all living cells
we notice certain senile changes which finally render them
incapable of performing their necessary function and death
is the result’ Why these changes take place is not known.
It can be readily understood that death necessitates reproduc-
tion, else the race could not exist. |

We notice certain conditions necessary to life. They are
moisture, temperature, light and air. In all living matter we
find a large amount of water in its composition. That this
degree of moisture is considerable can be seen for example
in the amoeba and human body. Absolutely dry matter is
incapable of living or of producing life. It is easy enough
to understand why this should be. Living bodies must be
more or less pliable that they may imbibe and assimilate food,
that they may grow internally and that they may move about
in search of food. (The extension of roots into the soil and
of trunk and leaves into the air, and other movements may be
considered as metabolic movements in plants.) Water being
a very mobile substance will partially impart its mobility to
those bodies containing it. Water does not go into chemical
union with living bodies. It enters, exists in and leaves the
body as water. Many of the lower organisms, as the fungi,
may be reduced to a state of considerable dryness before life
is destroyed. In this state they show no signs of kinetic life
and are to all appearances dead, but as soon as they are
brought into contact with moisture and a certain degree of
warmth they show signs of life. The actual amount of mois-
ture required to maintain life varies in different organisms.
The range of limit is quite narrow, for example, in man and
quite broad in fungi.

Temperature is closely associated with life. All vital
phenomena of assimilation, movement, reproduction, ete.,
are manifest within a certain range of temperature. As
temperature passes the limit of this range life ceases. The
limit varies greatly with different organisms and with the

52 BIOLOGY.

amount of moisture present. Generally it is found that a
greater degree of heat and cold can be borne when in a com-.
paratively dry state. Fungi have been exposed to a dry heat
of 120° to 140° C without being killed while none are sup-
posed to survive a temperature of 100° C when in a moist |
condition. No _ satisfactory experiments have been made
upon higher animals. Here the conditions of life are so com-
plex that it is very difficult to come to any definite conclu-
sions. In regard to cold it has been found that the tempera-
ture of torula could be reduced to —60° or —75° C ina dry
state before life action ceased ; while in a moist state —5° ©
was sufficient to kill them. It is known that some of the
protozoons flourish in the snow and ice fields of the arctic
regions and in high latitudes of the temperate zones. We
also find diatoms in the arctic and antarctic seas. As a rule
the maximum temperature which organism can bear is much
less variable than the minimum.

Light being so closely related to heat makes it at once
easy to comprehend that it must be necessary to life. Though
we find living organisms growing in absolute darkness, for
example fungi, plants in dark cellars and some cave animals,
though we find that light retards the growth of plants, yet
they required light originally to bring them into existence.
All living substances receive the influence of sunlight more
or less, either directly or indirectly. It is known that light
penetrates to some depth in soil and to a much greater depth
in water. Most organisms living to some depth under the
soil and water come to the surface more or less and are ex-
posed to the sunlight.

Spectrum analysis has shown us that light has caloric
and actinic properties besides its well known luminous prop-
erty. The most important chemical action that light exerts
is in the growth of plants. The various organic compounds
in the vegetable world owe their origin to the sunlight acting
as a reducing agent. Chlorophyll and starch production
cease almost wholly in its absence. Starch is supposed to be

BIOLOGY. 53

produced by the action of sunlight and chlorophyll ; others
again claim that starch is formed by small bodies called
leucoblasts. The best authorities seem to agree that starch
originates in chlorophyll and other coloring substances, but
mainly from these colorless starch generators called Jleuwco-
blasts. These are small and often hard to find. Jris Ger-
manica affords a good example in which to search for and
study them. )

Air is necessary to life because it consists of and holds
in suspension those substances required to sustain life action.
Free oxygen is taken up by all animals. Plants take up C
O., N H,, aqueous vapors, etc. Nitrogen acts only as a
diluent, else oxydation would go on too rapidly. H, O holds
air in solution for the fish and other water animals.*

One must keep in mind the relationship of plants and
animals. One is dependent on the other. Whatever is re-
quired by one is also directly or indirectly required by the
other. They both undergo a continual process of integration
and disintegration, a continual change in form. In nature
there is nothing zndependent. All combine to form links in
an endless chain.

As already stated, not the smallest particle of matter is
lost or useless, neither is the expenditure of energy or force.
The death of a plant or animal is only the act of giving
nourishment to some living plant or animal. The kinetic
energy of life in the present generation is finally stored as
potential energy to be again converted into kinetic energy in
some future generation. Thus force and matter are co-ex-
istent, immutable and indestructible. +

*Space does not permit a fuller discussion of moisture, tem-
perature, light and air. The student is requested to freshen his

memory on those subjects in some standard work on physics; also
the chemism of plant and animal life shouid be reviewed.

+ Some of my statements are necessarily broad, hence the stu-

dent is earnestly advised to do some independent thinking in order

that he may comprehend and not be misled. Confucius has rightly
said, ‘‘Study without thinking is labor lost.’

54 BIOLOGY.

Having briefly considered some of the properties of life
it might be well to consider its source and the relation of in-
organic and organic matter. We have good reasons to be-
lieve that at one time this earth was a large nebular mass
revolving in space. At this time it consisted of elementary
substances in a gaseous state. Where these substances came .
from is impossible to say. As already stated we can not well
believe otherwise than that force and matter were co-existent
and eternal, having no beginning and hence no end. this
matter acted on by this peculiar force became arranged and
rearranged. Finally the formation process made the environ-
ments suitable for the production of inorganic compounds.
The greatest factor to bring about these chemical combina-
tions was heat. We can produce compounds artificially by
causing elements to unite chemically on the application of |
heat. This chemism continued for ages till an exterior crust
began to form. It will be unnecessary to state that at this
time living matter could not exist. All the conditions were
foreign to life as we know it. Water existed in the form of
steam and vapor, the semi-solid crust was heated to a high
temperature. By and by the temperature was sufficiently re-
duced to allow the crust to harden and water began to con-
dence in pools, seas and rivers. Now we have the foundation
from which all subsequent life, vegetable and animal, sprang.
The same forces that formed inorganic compounds out of the
nebular mass continued to work and finally produced organic
matter endowed with a life principle, (mind, consciousness,
soul). This first life was produced from the inorganic com-
pounds at hand. No new elements or compounds were added.
Living matter contains the same elements that non-living
matter contains. The life mystery (lite principle) is to be
sought for in the combination of these elements. !

Chemists have been able to produce organic and inorgan-
ic compounds in the laboratory, but no chemist has so far .
been able to produce an organic compound endowed with a
life principle, not even the simplest. Living matter is too
complex for our present knowledge of chemistry. This life

BIOLOGY. 5A

principle we find in all living matter—in the amceba as well
asin man. It has not been located in any particular part of
the body. We know that it exists only from the fact that
we can observe its manifestations. This life principle is the
same in guality in all organisms. The only difference is that
of guantity.

The ‘‘instinct’’ of the dog is essentially the same kind
of manifestation as the wonderful ‘‘veasoning’’? in man. The
closer we study Biology the more are we convinced of that
fact. ; |

Spontaneous generation has been the subject of much
controversy. Its advocates had a strong following and still
has a few great scholars who teach that under suitable con-
ditions and surroundings some of the lowest forms of life can
originate de nova, that is spontaneously. Yet, the more care-
ful observers have been the more they are convinced that
Virchow’s dictum, *‘ Omnis cellula ab cellula,” istrue. There
has been no positive proof given that life, even the simplest,
can or does originate spontaneously. If that be the case and
admitting that the theory of evoiution is true, where did the
primordial germ or cell come from? The only reasonable
explanation is this: Though life does not originate spontan-
eously now, some time in the past the conditions and en-
vironments must have been suitable to develop a primordial
germ or germs. ‘This first living substance was no doubt
aquatic, neither vegetable nor animal, of the simplest struc-
ture, similar to our amceba. It was the primal parent of all
living matter.

It must be borne in mind that the process of evolution
has been at work or rather can be traced back to the remotest
part of our earth’s history. It formed a nebular mass ; it
formed inorganic and organic substances ; from these it de-
veloped species after species, each succeeding generation
more perfect than the preceding until the climax was reached
inman. This process does not stop here. It will continue
through all ages. We note changes to a higher perfection

56 BIOLOGY.

before our very eyes. The human race as a whole is pro-
gressing ; the whole animal world develops more complex |
species ; the vegetable world produces more highly special-
ized forms. Those structures that cannot fulfill the require-
ments of the evolution theory become extinct.

What is the life principle ( mind, soul, consciousness. )
What is its source? Is it something separate from the body?
The correct theory seems to be that the life principle is con-
comitant with and dependent upon organization of matter.
Matter must be combined and arranged as it is in the amceba
before it will manifest the life action of an amceba. It must
be arranged as it is in man before it can or will manifest a
definite ‘‘reasoning” faculty. We find that the more highly
developed an organism is the more highly developed is its
life principle. A morbid change in the body produces a cor-
responding change in the life principle. For example, com-
pare the ‘‘sowd”’ of a chronic dyspeptic with that of a man in
good health. Since mind (life principle, consciousness) is the
result of organization of matter it ceases with death or the
disorganization of matter.

In conclusion, I will give a schematic presentation of the
development of animal and vegetable life according to the
evolution theory. It is general and by no means perfect. It
will be noticed that the animal kingdom is somewhat higher
and later in development than the vegetable; alge are higher
than fungi, etc.

Space is too limited in a small work like this to go into
detail: The student is advised to read standard authors on
the subject of Biology. Remember the fact that you can not
become a real scholar in any branch of science unless you are
in favor of free thought and unless you are willing to study
wholly unbiased and unprejudiced by preconceived notions.

About one week should be devoted to the study of life. Lect-
ures by the professor in charge, supplemented by reading reference
books in a good library are recommended.

BIOLOGY.

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58 BIOLOGY.

YEAST, Torula Cerevisiae, (L., Zorus, a knot; and cere
: visia, beer. ) |

The torule have long been known by their power of
producing fermentation in sacharine substances. The whitish
substance that collects on the surface and bottom of ferment-
ing substances, for example, beer consists almost wholly
of these organisms. They are microscopic cells, consist-
ing of cell wall and cell contents, ranging in size from
1-1,000 to 1-2,000 of an inch in diameter. A cubic inch of
yeast may contain over a billion cells. Their structure is
very simple, a comparatively tough cell wall and a trans-
lucent, viscid protoplasmic fluid. In the smaller cells (the
undeveloped younger cells) may be found a roundish more
viscid portion, which is termed the nucleus or cytoblast (Gr.,
cytos, a cell; and dlastos, germ). In reproduction the cyto-
blast separates into two or more independent portions. These
surround themselves with a membrane thus forming new
cells. Reproduction goes on very rapidly. Sometimes a
number will adhere together, forming a “‘string” or ‘¢ group.”
Generally there is formed a more clear portion within some
cells termed a ‘‘vacuole” (L., vacwus, empty) whose presence
and function is not explained.

On the addition of H, S O, it is found that the cell wall
has two coats, an external and internal. The internal coat,
which resembles the intine in pollen, will contract with proto-
plasm. The external coat remains unchanged. Chlorophyll
is not present during any stage of its existence. Assimila-
tion takes place by asmosis. The torule, like the fungi, will
multiply in the dark and in sunlight.

Whether the torula belongs to the animal or vegetable
kingdom is a question hard to decide. It contains no starch,
no chlorophyll, it absorbs oxygen and gives off carbon
dioxide, it exists and multiplies without sunlight ; these prop-

BIOLOGY. 59

erties would indicate that it was not a plant but a member of
the animal kingdom. But the fact that the external cell wall
consists of cellulose and that it has the power of forming
protein out of a non-proteid compound, such as ammonium
tartrate, makes it almost decidedly a plant. [If the scientific
world would permit we might class it with Haeckel’s mowers
or third kingdom. But the majority are satisfied to call it a
plant, so it is probably better to adhere to their decision in
order to avoid confusion.

LABORATORY WorK.

Wash a little yeast so that nothing but the cells remain.
Place some on a slide and cover with cover glass. Examine
with +-inch objective and B ocular.

Yeast (Torule).

i. Rize:
1’ Measure carefully with micrometer.
2? Comparative size. (See note.)

2' Structure.
1’ Cell wall or sac.
1° Transparent, homogeneous.

2” Protoplasm.

1° Less transparent.

2° Often dots more or less transparent.

3° Vacuole, not always present.

4° Cytoblast or nucleus.

3' Form.

1* Make drawings of five or six cells.
4' Composition.

1? Cell wall.

1’ Amita little iodine solution under cover glass to
which has been added a drop of H, SO, The sac stains
bluish. This is the test for cellulose.

2” Protoplasm.

1° Iodine solution gives only a brownish discoloration,

hence no starch is present.

60 BIOLOGY.

2° Add a drop of caustic soda and copper sulphate
solution. A violet color proves that the protoplasm is a
proteid substance.

5* Physiology.
1’ Origin of torule.

1° Fill two flasks with culture fluid. Sterilize by boil-
ing flasks, contents, cork and all. Hermetically seal one and
allow the other to remain open. Examine the contents of
open flask from time to time. It will soon be found that the
open flask contains torule. After a time open the sealed
flask and examine. No torule will be found. This proves
that the torule do not originate de novo. It proves very
likely that torule in adry state float in the open air thus
gaining access to the flask. Where did the original torula
come from /

2? Growth of torule.
1° Fill three flasks, one with pure water, another with
a 10 per cent. solution of sugar, the third with the culture
fluid. Sterilize all three by heating to the boiling point for
a short time. Add a little yeast to each. Set them aside and
watch from time to time. In which flask does fermentation
begin first? In which is it the most active #

3” Life force of torule.

1° It is already known that boiling will destroy torule.

2° Fill three flasks with culture fluid. Keep them at
different temperatures. One at 80° F., the other at about
40° F., the third at about 15° F. In which is fermentation
most active 4

3° Dry some yeast by a moderate temperature. This
does not destroy its activity. ;

Note.— Examine different kinds of yeast. | Baker’s
yeast will probably be most easily procured.

BIOLOGY. 61
AMCEBA.—(Gr., ameba, change.)

The ameceba is very interesting because it represents the
lowest form of animal life, consisting almost wholly of un-
differentiated protoplasm. A description of its properties
has been given in the introduction to Biology which the stu-
dent is advised to re-read. Ameceba can generally be found
in stagnant water containing decaying vegetable matter. An
infusion of vegetable matter in water exposed to the sun-
light will almost certainly contain amcba, besides many
other forms of protozoons.

Amoeba are very simple in structure. The external limit-
ing layer or ectosarc can not properly be called a distinct
membrane any more than an oil globule can be said to have
an external coat. The ectosarec is simply of a somewhat
different consistence than the more internal portion. The
protoplasm generaily has numerous small granules scattered
through it. Sometimes a clearer portion called the vacuole
or contractile vesicle may be found in the protoplasm which
generally contracts with great regularity. The function of
this contractile vesicle is not definitely known. It is supposed
to pump water in and out of the body.

The ameeba is rarely at rest during life. Its continual
change in position and form is due to its power of extending
and retracting any portion of the ectosarec. These prolonga-
tions are called pseudopodia, meaning ‘‘ false feet.”” These
pseudopodia enable the amceba to move from place to place
and aid in finding and grasping its food, and also aid in
digesting it.

The food of the amceba consists mostly of vegetable
organisms. It appropriates these by wrapping itself around
them, thus making a temporary stomach of the ectosare. As
soon as it has assimilated all that it requires it unwraps itself,
and allows the useless portions to float away. Some bi-
ologists claim that the food passes through the ectosare into
the protoplasm and the undigested particles pass out through
the same channel.

62 | BIOLOGY.

The form of the amceba when at rest is spherical. This
may be proven by reducing the temperature to the freezing
point or raising it to about 100° F., or by a moderate electri-
cal shock. Either of these processes will render the amcba
powerless and leave it in a spherical form. A strong elec-
trical shock will kill them.

LABORATORY Work.

Place a drop of water containing amceba on a slide,
Cover with cover glass. Avoid pressure. Examine with
+-inch objective and B ocular.

Ameeba.

1* Form.

1? Note the continual change.

2? Note the development of a pseudopodia. The ectos-
arc prolongs first then the protoplasm follows after, often
with a sudden rush.

3° Make drawings at intervals of five seconds.

2' Size.

1’ Different in different species. Measure several.

3° Structure.

1’ Ectosare.

2? Nucleus. Sometimes absent.

3” Vacuole or contractile vesicle. Note its slow dia-
stole and rapid systole.

4’ Foreign bodies which have been swallowed.

5° Admit some iodine solution. If there is any blue
coloration it is due to starch granules which have been swal-
lowed.

4' Kinds. |

1’ Look for encysted forms. Some come to rest spon-
taneously, assume a spherical form and secrete around them-
selves a structureless sac.

_ 2? One species has very long aid slender pseudopodia.

Note.— Compare the amceba with white blood corpuscle.

BIOLOGY. 63

BLOOD CORPUSCLES.

Place a drop of blood well diluted with water on a slide
and cover with cover glass.

Blood Corpuscles. (Human. )

1* Red corpusc‘es.
1’ Relative number compared with white. Varies from
600 to 1,000 in health.
2? Form.
1° General form, disk.
2° Surface, concavo-convex on both sides.
1* Convexity near margin.
2* Concavity in center.
-3* Proof of form: If seen a little beyond the focus

the center appears dark ; if a little within focus the margin
appears dark. Due to the fact that the convex and concave
surfaces can not be brought to a focus at the same time.
3” Size.
1° Measure carefully with micrometer.
4’ Color.
1’ in masse, red ; single corpuscles, pale yellow or al-
most colorless. |
5? Movements.
1° None, except probably Brownian.
6° Tendency to collect in rolls (roleux.)
7? Crenated margin on becoming dry.
8” Nucleus.
1° None visible. Some physiologists claim that the
form of the red corpuscle is due to the contraction of its
nucleus

2' White corpuscles.
1’ Form.
1° Spherical, changeable.
2” Size.
1° Measure with micrometer and comparative size.
3” Motion.

64 BIOLOGY.

1? Ameeboid. Closely observe a corpuscle for a few
minutes. The change in form takes place very slowly. Make
drawings at intervals of one minute.

4? Nucleus, generally present.

5° Granular contents.

Note 1.— Examine the blood of ee birds, in-
sects, etc., and make comparisons.

are! 2.— The standard for finding comparative size of
microscopic objects is the red corpuscle.

CappILLARY CrrcuLation In Wes oF FRo«@’s Foor.

Catch an ordinary frog and put it in a bay just large
enough to hold it with the exception of one hind leg. Sew
the bag shut and tie it frog and all on a wooden stage in such
a position that if the free extremity is extended the web of
the foot will just come under the objective. By means of
thread tie the foot with toes extended over the opening
which you have made into the wooden stage for the trans-
mission of light. Finally tie the whole on the stage of the
microscepe. |

The foot can not be tied so that it will remain absolutely
quiet.

(a) Focus carefully and make your observations while
the frog is quiet.

(b) Observe elasticity of red corpuscles, elongating and
bending to adapt themselves to a given cappillary.

(c) White corpuscles have a tendency to adhere to the
sides of vessels and to migrate through the walls.

(d) There is no visible difference between venous and
arterial blood. Determine the difference by the direction of
flow.

(e) Observe effects of stimulants applied to frog and foot.

Note.— There is no test known to science by means of
which human blood can be unmistakably distinguished from
ali others. The spectroscope is said to have accomplished
what heretofore has been impossible.

BIOLOGY. 65

MOUNTS FOR THE MICROSCOPE.

TEMPORARY MOUNTS.

Temporary mounts are such not intended for future ex-
amination. The mode of preparing them depends on the
substance to be examined, for example vegetable tissues can
not be mounted like starch granules, nor pollen like blood
corpuscles. It would be impossible to describe each case in
detail. Only some general advice can be given. Good
judgment and reason will do the rest. |

(a) See that the slide and cover glass are perfectly clean
and dry. ,

(b) See that the substance to be mounted is free from as
much foreign matter as possible.

(c) Do not place a “‘ hand full” of the substance on the
slide, but only enough to show all the parts you wish to see.
Be sure that you do not place it all in a nice heap in the cen-
ter of slide, so as to make it impossible for light to pass
through it.

(d) The mediums most used for temporary mounts are
water and glycerine. Keep in mind the effect these mediums
have upon the various substances for examination. The
principal use of the medium is to dilute. For example if
undiluted blood were placed on a slide it would be impossible
to see separate corpuscles.

(c) Place a cover glass (use only the circular) on the sub-
stance. It retains the substance in place, spreads it evenly,
and prevents the too rapid evaporation of the mounting
medium. |

(f) Bear in mind the effect of heat and cold on what is to
be examined.

(g) Remember that cleanliness is a virtue much to be
desired in everything especially in microscopy.

66 BIOLOGY.

NEEDLE PREPARATIONS.

Mounts prepared by means of needles, called dissecting
needles, are termed needle preparations. They may be either
temporary or permanent mounts. The skillful microscopist
can do very satisfactory work by means of his dissecting
needles, although the mounts may be lacking in the beauty ~
of finish found in those cut with a microtome.

(a) Prepare two dissecting needles by fastening two
medium sized needles, heads down, into wooden handles of
convenient size and length. The needles should be highly
_ polished and sharp. If they are rusty it is almost impossible
to work with them. If desirable they may be bent in any
shape by first heating them to redness.

(b) It is very essential that one should have a dissecting
microscope. There are a great variety in the market, for
instance the ‘‘ Handy dissecting microscope” of the Bauch
& Lomb Optical Co., which I think can be had for one dol- —
lar. Their ‘*‘ Excelsior’ with three lenses costs $2.75. If
one has the means to make the investment it is best to get a
good binocular. Any person, however, with a little ingenu-
ity can construct a very creditable dissecting microscope for
himself as follows: Take a sound block of wood an inch
thick, four or five inches wide and about six or seven inches
long. In the middle of one end of this block of wood which —
we will call the stand, place upright a heavy (4-inch) piece of
wire about fonr or five inches long. Take a good large cork
in which make two holes, one for the heavy wire in the stand
and the other for a thinner wire which is to be bent so as to —
form a right angle with the heavy wire. The extremity of
the second wire furtherest away from the cork is to be bent
in a suitable shape to hold the lens. That is all that is neces-
sary. By means of the cork you can focus up and down.
By means of the second wire which works in the cork. the
lens may be swung from side to side. The lens of any sim-
ple microscope can be used. A plate of glass may be placed
on the stand so as to give a smooth clean surface to work on.

BIOLOGY. 67

Any kind of hand rests may be placed on either side of the
stand. Maving, by a little ingenuity and mechanical skill,
devised the necessary apparatus you may begin preparing
mounts. It can be readily seen that only soft tissues, such as
muscle, tendon, fascia, etc., can be used.

(a) Take a piece of tissue about the size of a pin head,
place it on the glass plate of your dissecting microscope and
begin to separate the ultimate fibres by means of your dis-
secting needles. Keep the tissues moistened with an alkaline
solution (NaCl sol.). Tease just as long as there is any thing
left to tease. The ultimate fibres must be separated. Itisa
tedious task, but practice patience which you must do before
you can become a microscopist or anything else. After be-
ing convinced that the substance is sufficiently teased proceed
to the next. |

(b) Remove as much moisture as possible by means of
blotting paper. Drop a few drops of 85% alcohol on tissue,
allow it to remain a few minutes, then remove by means of
blotting paper. The alcohol hardens and contracts the ulti-
mate histological elements somewhat, thus making them more
conspicuous under the microscope. It also prevents decom-
position of tissues.
| (c) Now add a few drops of staining fluid. Carmine is
probably the best for animal tissue. Allow it to remain till
well stained. The object of the staining is not to make the
mount appear more beautiful but to render the various _histo-
logical elements more prominent. The nucleolus stains more
heavily than the nucleus, and the nucleus stains more heavily
than the cell contents. Remove staining fluid by means of
blotting paper. If stained too much wash out excess by
means of washing bottle.

(d) Fix the stain by allowing specimen to remain for a
few minutes in acid alcohol. (See recipes). Remove alcohol.

(e) Now put on a drop of oil of cloves. This makes
the tissue transparent. Remove oil and dry the specimen
in a moderate temperature.

68 BIOLOGY.

(f) Mount in balsam and finish like any permanent
mount.

A

Note 1.— Be careful not to have too much tissue on the
slide. Remember that a very small particle will appear large
under the microscope.

Note 2.—Do not have the fibres all in a bunch but separ-
ate them as much as possible.

Note 3.—Do not be slovenly and careless. Good mounts
can be kept for a long time.

PREPARING ANIMAL TIssvUES TO BE Cut By HAND OR WITH A
MICROTOME.

‘Some soft tissues can not be teased and mounted as has
been described in the foregoing process. For example
glandular tissues, such as liver, kidney and _ parotids; also
such tissues as lung, cartilage, muscular tissues with trichina
in situ, etc. They require special preparation. It would be
impossible to describe the best way for mounting each tissue.
The student must keep in mind the nature and composition of
the tissue he is about to work upon and the properties and
actions of the various reagents he is going to use.

The following process is general. Does not apply strict-
ly to any one tissue. The different steps throughout this
book are arranged with the supposition that the student
spends at least one hour a day in the laboratory.

PREPARING TISSUE FOR SECTION CUTTING.

(a) Preparing specimen.—Cut the tissues in pieces one
inch square or less. Make either longitudal or transverse
squares or both. Wash away blood, dirt, etc. Then place
in a cold saturated solution of Hg Cl, Leave it one hour,
then remove and wash free from all traces of the sublimate.
(See recipes. )

:

BIOLOGY. 69

(b) Hardening.—Place in 65% alcohol for twenty-four
hours. Then in 85% alcohol for twenty-four hours. Now ex-
amine the tissue to see if it is nearly hard enough, if so place
in 90% alcohol for one hour. [f not nearly hard enough, it
must be allowed to stand for another twenty-four hours or
more in fresh 85% alcohol.

(c) Staining.—Place the tissue in the staining fluid twen-
ty-four hours, till stained throughout. (Cut and see.)

(d) Fixing the stain,—Piace in 70% alcohol to which has
been added a few drops of H Cl. Leave an hour or so, till
it turns a bright scarlet with carmine stain. It must not be
stained too much.

(e) Dehydrating.—Place in 70% alcohol for twenty-four
hours. Remove and place in absolute alcohol for one hour.

Clearing.—Place specimen in oil of cloves for twenty-
four hours. The oil dissolves the aleohol and makes the
tissue transparent.

(f) Prepare for Imbedding.—Place the specimen in eqnal
parts of oil of turpentine and paraffine heated over water
bath for half an hour. Do not boil it. Then into paraftine
heated over water or sand bath for one-half hour.

(g) Imbedding.— Make a paper box suitable to the size
of the specimen. Place in it the specimen, and imbed it in
melted paraffine. |

Note 1.—This is one of the many ways of preparing a
specimen for the microtome and probably one of the very
best. The different steps are so arranged as to save you both
time and extra labor.

Note 2..—_Observe each step and study out ‘‘why” you
should do this and that. Remember that the various tissues
treated alike will not give like results.

70 BIOLOGY.
CUTTING SECTION.

(a) Cutting with a microtome.

(1) Make either transverse or longitudal sections.

(2) Cut as many sections as desired, and place in a
clean box properly labelled.

(b) Cutting by hand.

(1) Do not cut too thick.

(2) Hold the section firmly in the left hand, and draw
the razor at full length, evenly and smoothly toward you.

(3) Do not ‘‘ saw off” a section.

(4) Cut one section, look at it and if you think it is thin
enough, mount it and see ; if not thin enough, discard it and
try to do better the next time.

(5) Keep razor and specimens dry and clean.

(6) Last, but not least, keep your razor sharpened to-
the keenest edge.

MOUNTING A SECTION.

(a) Cleaning slide and cover glass.—Remove all foreign
matter by proper agents. Wipe perfectly dry with a clean
cloth. |

(b) Remove paraffiine—Lay one end of cleansed slide on
some eminence, so as to incline it about five degrees. Place

a section near center of slide. By means of pipette drop —

some benzine on the upper edge of the slide and let it run
down. Allow all paraftine to dissolve and wash away.

(c) Removing benzine.— Remove as much benzine as
possible by means of adry cloth and blotting paper.

(d) Drying.—Warm the slide with specimen moderately
till dry and then place specimen on exact center of slide.
Find exact center of slide by means of slide centerer.

BIOLOGY. 71

(e) Mounting.—Place a well cleaned cover glass on top
of the section. Deposit a drop of balsam around the margin
of the cover glass; capillary attraction will draw it under
and spread it evenly. Press slightly and carefully, per-
pendicularly on the cover glass.

(f) Examining the section.

(1) Examine with low power, (1-inch) objective. See
if it is of right thickness, and if it shows the proper arrange-
ment of tissue.

(2) Examine with high power, (4-inch) objective. See
if it shows all the histological elements, cells, nucleus, nucleui,
etc. If the section does not meet a microscopist’s expecta-
tions, remove from slide at once.

(3) If it is a good section remove air bubbles from
under cover glass by carefully heating over spirit lamp till
bubbles escape. .

7th step.—Finishing.

(a) If the section isa good one, lay it aside for several
weeks, till balsam is dry; then remove all superfluous balsam
by means of knife, alcohol, and dry cloth.

(b) Place on a turntable and make a ring of oxide of
zine around the margin of the cover glass. It may be artisti-
cally finished by means of colored varnishes.

(c) Labelling.

(1) Paste label on the right hand of the slide, (the up-
per side). Put on name of section, whether cross section or
longitudinal; below that, your name and date.

(2) It is well to place label also on opposite end on
which write reagents used: 1. What hardening agent. 2. Im-
bedding material. 3. Staining fluid. 4. Mounting medium.

Note 1.—When examining a slide under the microscope,
try to see what there is to be seen. Do not merely satisfy a

72 BIOLOGY.

morbid curiosity. Study what is before you in some standard
treatise on the subject.

4

Note 2.—Examine first with low power, and then with
high power. In using the microscope, handle with care. —
Learn to keep both eyes open and to use them alternately, so
as not to ruin your right eye.

VEGETABLE TISSUE.

Raw material for this branch of study can be found
everywhere. The vegetable kingdom furnishes more interest-
ing object for study than all other classes put together.
Starch, which is so plentifully distributed throughout the veg-
etable kingdom, has been described elsewhere ; also pollen.
Among the lowest forms of animal life are the alge. (L.,
alga, sea grass). They are easily procured and afford an in-
teresting study. They grow in water and may be found in
the ocean coloring its water, in rivers, lakes, ponds, ditches,
etc. The green scum so often seen on the surface of stag-
nant water consists of these small plants. Put some vege-
table tissue in a beaker full of water and expose it for several
days to the sunlight. It will contain a large number of alge.

Lasporatory Work.—Alge.

Place a drop of water containing alge on a slide and
cover with cover glass. Examine with 4-inch objective and
B ocular.

Algee.

1’ Kinds.

1? Single celled or unicellular.

1° As to form.
1* Spindle lke.
2* Rod like.
4° Spherical.

BIOLOGY. 73

2” Many celled or mubticeilular.
1° Double celled.
23 Those in which cells are united so as to form a

string. Often very long.
: 3° Those in which ce!ls are united in a group.

2’ Structure of a single cell.

1? Cell wall.
2? Cell contents.

3* Composition.
1? Celi wall
1° Cellulose.
2° Earthy salts.

2? Cell contents.

1° Albumen.

2° Coloring matter, generally colorophyll.
3° Starch granules.

4° Oily substance.

4* Assimilation.

1’ Endosmosis.
1’ From the water in which they live they take in C

O, and N H,.
- 2? Exosmosis.
1* Give off oxygen.
2° Surround themselves with a slimy coat.

5' Admit a drop of iodine solution under cover glass and
note results.

6 Make exact drawings of the different kinds of alge.

7: Take two beakers containing algse, place one in the sun-
light, the other in the dark. Note results.

The following process for mounting vegetable tissue is

general, hence the student must use judgment in what he is

74 BIOLOGY.

about to undertake. Vegetable tissue is plenty and easily
procured and with care very nice mounts can be made.

PREPARING FOR SECTION CurTTING.

(a) Bleaching.—Get two wide mouthed ounce vials. Pro-

vide one with a perforated rubber cork. In one vial place -

some Mn O, and H Cl, insert the rubber cork containing the
short end of a U-shaped delivery tube. Pass the other end
of the tube into the second vial containing water and the
vegetable tissue. Chlorine will now be generated. Mn O,
+ (H Cl), = Mn Cl + (H, O), + Cl, which bleaches the veg-
etable tissue. Allow it to stand for twenty-four hours.

(b) Eliminating chlorine.—Place the tissue in a solution
of Na, 8 QO; (one part of Na, S O; to 30 parts of H, O) for
half an hour, then rinse thoroughly with pure water.

(c) Remove air from tissue.—Place it, immersed in 20%
alcohol, under the receiver of an air pump. Pump till bubbles
cease to be given off. Diluted alcohol prevents the forma-
tion of algee and other vegetations.

(d) Prepare for imbedding.—Dry by means of blotting
paper, then dip into Davis’ solution, withdraw and allow to
drain on blotting paper till surface is dry.

(e) Imbed, cut and mount same as animal tissue. Sec-

tions must be cut as soon as possible, else the tissue will be- |

come too dry and hard to cut. Keep the sections in diluted
alcohol (20%) till ready to mount.

BONE.

Bone on account of its hardness requires special prepara-
tion. Beginners generally have good success in making a
section of bone. The following process is probably the best
for mounting a section of dry bone in which the lining mem-

ee a

BIOLOGY. 75 ©

brane of the Haversian canals and lacune has been destroyed
and removed.

i.

PREPARING FOR MovunTING.

oe Getalong bone. With a bone saw saw off some
transverse and longitudinal sections making them as thin as
possible. Make the sections from the compact portion of.the
bone. |

(b) Thin down the sections by means of -an ordinary file.

(c) Place the section between two ‘‘Washita” or sand
stones and rub till the section is so thin as to bend of its.own:.
weight when one end is raised. The grinding surfaces of the =.
stones and section must be kept moist all the time. Grind.
carefully.

Il.

MoountIinca.

(a) Boil some Canada balsam till it is quite thick. When
cool place a drop of this balsam on a cover glass and allow it
to cool till it is of the consistency of putty or butter, then
imbed in it the section of bone. Place cover glass with
section downward on exact center of slide. By pressure get
rid of as much superfluous balsam as possible ; apply a little
heat if necessary. If mounted in thin balsam the lacune
will become filled up and spoil the section.

(b) Finish like any other permanent mount.

Note.— Rock sections can be made in a similar way.
They, however, require more care and patience.

76 BIOLOGY.
INSECT MOUNTS.

Small insects can generally be mounted whole without
any previous preparation since they are. mostly transparent.
Among these may be mentioned Acarus domesticus, young
Pulex wrritans, Acarus scabies, and especially the younger
members of the genus Pediculs.

The larger insects, such as flies, bees, beetles, spiders,
etc., require careful dissection in order to gain a correct in-
sight into the relative structure of the insect economy. It
would be impossible to describe how to proceed in each in-
dividual case. Experience comes by practice and the student
will find that each subject becomes more and more easy,
especially if, before commencing in haste with the needles
and scissors, he will study the general arrangement of organs
in his subject, by reference to some one or other of the many
standard works in existence at any good library.

The student will have no trouble in finding insects for
dissection. Put no insect to any unnecessary pain. Kill it
us soon as possible by means of chloroform, ether, or the
cyanide of potassium bottle which is now so often used.

Betore begiuning work be sure you have the necessary
instruments such as dissecting case, dissecting microscope,
dissecting needles aud the necessary reagents. Now select
some insect to begin with, for example the Gryllus domesticus
or common cricket.

bs

PREPARE FOR DISSECTING.

(a) Carefully study the insect before you, referring to
some standard work. Be sure you know what it is and can
classify and name it rightly. Be sure you understand its
mode of living and the structure of its organs. In fact find
out all you can about it before beginning to dissect. Of
course while doing this you will very dilligently use a good
_ pocket lens and finally make a good drawing of the whole
insect.

BIOLOGY. 77

(b) By means of knife, scissors and forceps, detach wings,
legs, autenne, eyes, tongue. Portions of these if trans-
parent enough can be mounted, otherwise they can only be
examined as opaque objects. For example never have a
mount which shows the foot of an insect very beautifully and
has attached to it those portions of the leg which are much
too thick and opaque to show anything at all,

(c) Place the carcass of the insect back down on a slide
containing a drop of hardened balsam. Allow it te become
firmly fixed. | |

(d) With a pair of fine scissors carefully slit up the in-
tegument on both sides. Raise up the chitinous skeleton and
clear away the attachments with a blunt needle. When this
is tolerably well performed the whole of the organs may be
seen 77 situ.

(e) The specimen should now be placed for twenty-four
hours in a mixture of glycerine and water (one of glycerine
and two of water). This softens it for better dissection.

Note.—In this operation it is supposed you are about
to dissect out the digestive organs. If the nervous system
- were wanted it would not do to immerse it in a glycerine so-
lution as that would only soften the already too delicate
tissue more. Instead it would have to be immersed in
dilute alcohol.

ET.
DISSECTING.

(a) Place the specimen, still imbedded on the slide, in a
dissecting trough under the microscope. For dissecting trough
you can use any low dish or pan. Keep the specimen moist
with the glycerine solution.

(b) Brush away all loose tissues with a small camel’s hair
brush. With scissors, needles and brush separate and clear
away all that does uot belong to the digestive organs. Never
allow the specimen to become dry.

78 BIOLOGY.

(c) By means of the scissors lay open the gizzard and
wash it out with wash bottle and brush.

1:

Mountina.

(a) Place the different organs in their natural position on
center of slide. By means of blotting paper remove as much
moisture as possible. Do not allow the specimen to become
dry.

(b) Mount in pure glycerine. Glycerine mounts require
careful preparation. Care is required to prevent them from
leaking.

(c) Attach cover glass to slide by making around it a ring
of balsam. After some time finish with varnish, etc.

GENERAL ADVICE.

Some advice has already been given about finishing bal-
sam mounts. By careful study and consideration the observ-
ing student will find the best way to finish any mount he may
have. |

The intrinsic value of a mount does not depend upon its
artistic finish ; but first, upon the fact that the section itself
has real value. For example the digestive organs afford more
interest than simply the chituous skeleton, although it may be
entire and look very beautiful. Secondly, upon the fact that
it is well finished so that it can be kept as long as possible.
[f combined with these two qualities we can have beautiful
finish so much the better.

Always label each slide carefully. It avoids confusion
and much unnecessary labor. Labels are cheap, get a good
supply and paste them on well. In labelling insects always
put on the scientific name, giving genus and species. If there
is room you may put on the common name also.

Do not throw mounted slides into any box like marbles.
Such a procedure will soon ruin them if they were ever worth

BIOLOGY. 79

any thing. Place them in order in slide boxes made for that
purpose. Place slides so that when the box is opened the
labels naming the mounts will appear on the right hand side.

Be sure that each box is properly labelled and classified
_ and that all the boxes have a suitable case in which they can
be kept. One box might be labelled as follows:

Series No. 0.
Digestive and Tracheal Systems.

Articulata, (Subkingdom).
Insecta, (Class).
Diptera, (Order).
Muscade, (Family).

Genus and species are given on the label on slide. Or,

Series No. 8.
Animal Tissues.
Muscle and Tendon,
Needle Preparation.

Each slide box is made to hold twenty-five slides. In
getting slides it is best to buy those with ground edges as they
will not scratch your microscope.

Above ail keep only good mounts. Poor ones are of no
use to you or any one else. Vo not become discouraged if
you fail in the first dozen attempts. If you have any ability
at all you will finally come out victorious with a good mount.

Study your slides thoroughly and carefully. Be sure you
know what you have before you. Get the necessary books
in some way. One thing that the beginner generally lacks is
application. Keep your mind fixed on what is before you.

Get your drawing outfit and make drawings of what
you examine. It will help wonderfully to bring out details
and to fix them upon your mind.

BACTERIA.
In recent years much has been said and written about
the role that the very innocent and harmless looking bacteria

80 BIOLOGY.

is supposed to play in the animal economy. Im some in-
stances it has been proven with almost a certainty that they _
are capable of causing morbid changes in the natural cell
function of the animal system, thus producing what is called
disease.

Bacteria are very minute, consisting of protoplasmic
matter devoid of chlorophyll, sence multiplying by trans-
verse division. They are of different forms, oblong, globu-
lar, rod like, spiral, etc. Many exist in two kinds of condi-
tions, a still and an active. |

Like torule they are capable ot exciting fermentative -
changes in substances in which they live. All the putre-
factive changes in animal and vegetable bodies are brought
about by these bacteria. Here again we find the truth veri-
fied that death of one organism means life to another.

‘Drying does not kill bacteria. In the dry state they are
not active but as soon as they find a suitable nidus they will
begin to be active and reproduce their kind. The air, water,
and surface of the earth are supposed to be full of bacteria.
The reasons why their evil influence on bodies is only felt at
certain times.are these: First, they may not be present in
sufficient number; and second, the body upon which they are
acting may not be in a suitable condition. Organic cells in a
normal state have sufficient physiological resistence to with- ©
stand the attacks of these germs. But as soon as this physi-
ological resistence is lowered, tor example in the human
body by improper diet, the germs are able to locate and feed
upon such cells, thus producing a pathological condition of
an organ or some disease, as diphtheria, that aepending upon
the majority of germs which attack the body at the i
moment.

On account of the! small size of most bacteria the be-
ginner is not able to accomplish very much. |

LABORATORY Work.

Infuse some hay in warm water for an hour. Filter and
set the filtrate aside for twenty-four hours. Note changes.

BIOLOGY. 81

Examine the infusion with 4-inch objective and B ocular.

Bacteria.
1’ Form.
1° Rodhke or elliptic.
2? Size.
1’ Several times longer than broad.
3* Structure.

1* Not much to be made out with such low power. An
external transparent layer and the internal protoplasmic fluid
containing darker substances.

4* Movements.

1* Some active, some passive.

2” Some imbedded motionless groups.

Bacillus.

1’ Longer than bacteria.

Spirocheta.

"so sorm.
1’ Like a spiral thread.
2* Motion.

1’ Very active. Spiral movement upon its longitudinal
axis.

3 Uncommon form, often found in decaying teeth.

Place some hay infusion in three flasks. Boil two of
them for afew minutes and hermetically seal one. Set all
three aside in a warm place. Compare the three flasks. Ex-
plain.

Noles:
Davis’ Solution.

Acaciz Gummi.. gr. EX. Iodine

Glycerine. 2. ett. V.:
ATeaHOli a. e. 4. gtt. X.
Reuss. ay

Allow all the gum arabic |

HBO. 5 Peas.

to dissolve, then filter care- |

fully.
No. 2.
Sulphite of Sodium.. 5.
Aer ads). % dark oe Olv.

Allow all of the No. 2 8 QO, |

to dissolve, then filter.

WD. 3:
Ohimacher’s Medium.
Canada balsam...... ib
Ohierotorta-3 p05 Fl.
Mix and shake well.

thick add more chloroform.

No. 4.
Corrosive Sublimate Solution.

ss i Sa 5 ee OL,
Hydrargiri Chloridi cor. q.s.

Make a saturated solution |
It is a |
very powerful poison. As an |
antidote give albumen, the |
white of an egg, flour, milk, | .
| 34 ounces, shake and filter.

and filter carefully.

etc. Give an active emetic.

If too |

| filter.

|

Wo. 52
lodine Solution.

; ee gr. XL.
Iodine Pottasium, gr. LX.
Water ad Oi.

Dissolve the two first named
substances in 3iv. of water,
then add the remainder, filter.

No. 6.
Gum Water.

R
Gum Arabic

ath. Slv.
Glycerine <<. 3am ett x
Carbolic Acid ..... ett v.
Aqua, ads... J. 5iv.

This is an excellent medi-
um for attaching labels to
glass. .

NOX a
Picro Carmine.
R
Carmine Powder, gr. XV.
Liquor Ammonia, a:
Distilled Water, Vid:

Mix and add _ Picric-acid
Powder 514. Shake well and
Now set aside for sev-
eral days to evaporate. The
powdered residue must be
kept in a well stopped bottle.

When ready for use take of
the above Picro-Carmine pow-
der 30 gr. and distilled water

RECIPES. 83

No. 8. | Woovrr.
Ammonia Carmine. Acid Alcohol.
Carmine Powder. .... ol. 4 Pleohohee wi hee see Sil.
Liquor Ammonia ... ss. 18 Se Bi De ah Sai oN ett X.
While stirring add distilled
. water 5XV., filter and keep No 1s
ee 9 Pottle. iin: Varnes
No. 9. (For colored rings. )
Preservative Fluid for In- 7] ne
Movs ey are made by mixing
t _. | the various colors with the
Chloral Hydrate. Sl. | vehicle in a mortar.
Sodium Chloride... gr. xv.
Pottassium Nitrate, gr. xxx. VEHICLE.
Glycerine and Alco- Dammar Gum..... 02. ili
Hore@e......... o%iss.| MasticGum:....... oz. i.
Meee Ve cb ASGRATI Ere, om te ues OZ. Vi
Dissolve the chloral in the COLORS.
water and the remainder sep- | White ede of wine
arate. Mix and filter. ' Blue | : | | . . | . Laas
No. 10. | 1 (0 Ra i Carmine.
Culture Fluid for Torule. | Bigeloste hie 28 Lamp-black.
PG EPeGH wenn h ee: en. Verdigris.
"Potass. Phosphate, gr. X. Pre gels ree ae Chrome yellow.

Magnesium Sulph., gr. V. When the benzine evapo-
Ammoninm Tartarate, -35i. rates it leaves the colors in a

Cane Sugar...... 5iss. powder. Either use more
Meet SIV. benzine or simply dip the
Mix and filter. _ brush in benzine.

It is best to buy the staining fluids all ready prepared,
especially where only a small quantity is required. The re-
maining formule the student will have no trouble in prepar-
ing for himself.

VEGETABLE HISTOLOGY.

Having considered the process of making sections for
the microscope we shall now describe somewhat the general
histology of vegetable tissue. Distinct tissue are not found
in the lower plants, not till we arrive atthe pteridophyta.
(ferns, cycads.) The most important tissue is the vascular.
This begins to develop in the highest bryophyta (moss)
but can not be said to be fully developed till we get
to the ferns and flowering plants. Epidermal tissues is first
to be differentiated. It constitutes the primary covering of
the plant, consisting of one, but sometimes of tw» or three
layers of cells. Init are found the stomata and trichome
elements, which are simply modified epidermal cells. Scler-
enchyma or sclerotic tissue consists of cells whose walls are
very much thickened, commonly called stone cells. | Collen-
chyma is a tissue whose cells have very much thickened
angles; the cells themselves are generally prismatic in form
and always found in close proximity to epidermal tissues.
Cork tissue is also found beneath the epidermal tissue ; its
cells are thin walled, there are no intercellular spaces and at
maturity lose all their protoplasm and become filled with air.

All these tissues, no matter how much they may differ,
originated from a single parent cell. A general description
of the cell is now in order. Heretofore the cell was con-
sidered the unit of structure in living organisms, this is prob-
ably not so, as [ shall explain later on. Generally the cell is

86 VEGETABLE HISTOLOGY.

defined as a neucleated mass of protoplasm. Sometimes
even the nucleus may be absent so far as we know. In such
cells it is supposed that the nucleus is finely divided and dis-
tributed through the protoplasm. Cell, is an unlucky term
since it conveys the idea of an enclosure. The early histolo-
gists supposed all cells to be simply closed sacs and the very
subordinate nature of the cell wall was not understood. We
now know that the protoplasm and not the cell wall consti-
tutes the essential part of the cell. In most cells we find sus-
pended in the protoplasm a more highly refractive body, the
nucleus. It consists of a delicate network of fibres suspend-
ed in a more clear substance surrounded by a delicate mem-
brane. The clear portion is called achromatin and the net
work chromatin. The readiness with which the nucleus
stains is due to the chromatin. The achromatin does not stain
as readily, some staining fluids do not stain it at all. In the
chromatin is imbedded a highly refractive body, the nucleo-
lus. It is simply a more dense collection of chromatin. As
a rule there is but one, but several may be found in some
cases. Sometimes a nucleus is found within the nucleolus.
McMillan has discovered imbedded in the nucleus certain
highly refractive bodies very difficult to stain. Their function
and presence is not yet accounted for. The fact is there are
yet many mysteries of cell structure to be unraveled and

many more will be discovered. |

The cell wall is secreted by the protoplasm and consists
principally of cellulose in the vegetable kingdom. It is an
amyloid carbohydrate having the same farmula as starch.

The thickness of the cell wall varies greatly. Sometimes
peculiar regular markings are formed by this thickening pro-
cess going on unevenly, depositing the cellulose in heaps as
we find in pollen. Sometimes the deposits are formed on
the inner surface of cells as in ring, spiral and pittet vessels.
In cells that become free just before maturity (as in pollen)
these markings are formed on the outer surface of cell wall;
when cells unite to form tissues the markings occur on inner

VEGETABLE HISTOLOGY. 87

surface as in the different vessels of the vascular bundles.
Sometimes the cell wall becomes otherwise changed in ap-
pearance and chemical behavior asin cork and lignin (wood).
It may become infiltrated with coloring matter and mineral
salts. The outer portion of wall may become converted into
mucilage or gum as in the quince seed or flax. Sometimes
the wall becomes partially or entirely absorbed due to pres-
sure of cells upon each other as in the formation of laticifer-
ous tubes for example. These changes in the cell walls are
of considerable commercial importance, yielding gums and
resins besides other useful substances. Crystals of various
kinds also occur in the cell wall, yet tliese crystals are mostly
found in the cell contents. Infiltration of mineral matter,
especially Si O,, for the purpose of strengthening the cell
wall often occurs, especially in grasses.

Pfeffer claims that the cell wall, in fact nearly all tissues,
are made up of small particles which he terms ‘ micelle”;
they are very minute crystalloidal particles, each one consist-
ing of many molecules, yet too small to be seen with the aid
of the best microscope. These particles are not in contact,
but separated from each other by a layer of water. This
water is taken up and held in place by capillary force. The
increase in size of tissues on the addition of water is due to
the fact that the layer of water is increased thus forcing the
‘‘micellee’ further apart ; when the water evaporates the mi-
celles approach each other and cause the cell to shrink.
Starch granules, coloring bodies, etc., are likewise said to be
made up of these micelle. Pfeffer’s assumptions are so far
purely hypothetical. I have simply mentioned it to let the
student know that there is such a hypothesis maintained by
one of the greatest botanists.

Protoplasm is the most important part of the cell. It is
the basis of all living matter. Yet in spite of its importance
but little is known concerning it. Typical protoplasm is a
transparent, semifluid or viscid, granular substance. It con-

88 VEGETABLE HISTOLOGY.

tains the elements C,O, H, N, some 8 & P. These combine
to form very complex proteid compounds whose percentage
composition is not known. These compounds are quite un-
stable and can readily be broken up into simpler compounds.

The properties of protoplasm may be divided into four
kinds, namely,

1. Chemism.

2. Metabolism.
3. Motility.
4. Reproduction.

These properties are found in all living protoplasm and
distinguish it from dead matter. All the phenomena of life
action are dependent upon these properties. Chemism may
be detined as the property which protoplasm has of produc-
ing within itself spontaneous chemical action thereby chang-
ing its chemical equilibrium. This chemism continues during
the whole life period of every particle of protoplasm. Ces-
sation of chemism means death to the protoplasm. The
cause of this chemism is not known.

Metabolism is the process of assimilation and the excre-
tion of waste products. It is the result of chemism.
Through this metabolic process protoplasm increases in
amount and forms the many bi-products, such as cellulose,
starch, chromatophores (coloring bodies), aleuron grains, etc.,
and the waste products which are no longer of service to the
cell.

Motility is that property which protoplasm has of pro-
ducing within itself amceboid and other movements. This is
also dependent upon chemism. Berthold made a careful
study of protoplasmic motion and explains it wholly mechani-
cally. In order to understand him a careful study of surface
tension is necessary. (The student is referred to any stand-
ard college text on physics). Before a liquid or semi-liquid,
free or suspended in another liquid, can come to rest or as-

VEGETABLE HISTOLOGY. 89

sume a fixed form, surface tension must be equalized or
counteracted on all sides. Movements of oil globules sus-
pended in liquids, which are quite common, are due to a dif-
ference of surface tension between the oil globule and the
liquid. As soon as surface tension is equalized movements
of all kinds cease. If by some means the surface tension is
continually changed motion is continuous. In living proto-
plasm chemism is the property which continually produces a
difference in surface tension and hence movements of various
kinds are the result. The movements of amceba, white blood
corpuscle, bacteria, most infusoria, desmidia,algee, and stream-
ing movements in vegetable cells are explained on this basis.

Reproduction is the property which one particle of pro-
toplasm has of spontaneously separating into two independ-
ent masses. ‘This will be more fully discussed under cell
division. 4

R. Hartig has recently advanced a hypothesis which if
correct will explain the source of protoplasm. By treating
protoplasm with K HO or NaH O it is dissolved and leaves
behind minute highly refractive bacterioid bodies which he
terms ‘*‘Zeil Granula” or ‘‘ Elementar Organismen.” He
claims that they are living organisms and by their life action
secrete the protoplasm in which they live. This secreted
protoplasm is not a waste product but is reaily a part of these
organisms, as much so as the gelatinuous covering of bacteria
or the shell of molusca. If this hypothesis be true then the
cell is not the wnt of structure but each cell consists of a
multitude of sempler units, the * Zell Granula,” which pro-
duce protoplasm.

Cell division takes place by two methods, direct and _ in-
direct. The direct method is rare and occurs only in the
lowest organisms. Here the nucleus constricts and separates
into two, finally the whole cell is divided into two. In the
indirect method the nucleus undergoes a peculiar transforma-
tion before it divides, called karyokinesis, It is but very re-

90 VEGETABLE HISTOLOGY.

cently that karyokinesis has been studied and explained.
Roughly it might be described as follows: (1) Nucleoli dis-
appear. (2) Chromatin threads break up into U-shaped
pieces. (3) Cross striations, which are present in the chro-
matin, disappear, (4) U-shaped pieces arrange themselves
so that the closed ends are placed perpendicular to the equa-
torial plane of nucleus. (5) Appearance of two achromatin
poles diametrically opposite and at right angles to equator.
(6) U-shaped pieces each separate into two, one part passes —
to one pole the second part passes to other pole. (7) Reap-
pearance of cross striations in chromatin. (8) Reappearance
of nucleoi and cell division is complete. While this process
has been going on-in the nucleus the protoplasm and cell wall
also became constricted through the middle and finally
divided.

In the cell are also feund cell sap, leucoblasts or amylo-
blasts which are supposed to form starch, aleuron grains
containing crystalloid bodies, starch, acids, fixed oils, volatile
oils, gums, resins, sugar, pariienes crystals, especially of
calcium oxalate, coloring matter of which chlorophyll is most
common, aromatic compounds and many other substances.

TISSUES.

As already stated all tissues develop from a single cell.
Even after cell division has gone on to considerable extent
no noticable differentiation of structure takes place. Sooner
or later three primary meristematic tissues can be seen,
namely, dermatogen, periblem and plerome. These can be
studied in very young growing rootlets of ferns and angio
sperms. Select the smallest fern rootlet obtainable and
mount whole in water. It will show a structure something
like that in. Fig. 4, lower right ‘hand corner. c, is the tri-
angular apical cell from which all tissues arise ; a, is the root
cap which serves to protect the growing point of roots ; b, in-
dicates the dermatogen, the primary» epidermis, from whi

_ VEGETABLE HISTOLOGY. 91

all epidermal structures develop: e, represents the periblem
from which the ground tissue or parenchyma proper develops ;
d, is the plerome cylinder or primary vascular bundle system.
In the dicotyledonous angiosperms tissues develop from a
group of apical cells. Study these primary tissues in the
rootlets of ferns, monocotyledons and dicotyledons.

The principal tissues are—

_ (a) Vascular tissue or ducts.
(1) Ringed vessels.
(2) Spiral vessels.
(3) Pitted vessels.
(4) Reticulated vessels.
(b) Parenchyma or ground tissue.
(c) Collenchyma or thick angled tissue.
(d) Sclerenchyma or stony tissue.
(e) Liber or wood tissue. (Xylem.)
(f) Tracheids or vasiform tissue.
- (g) Sive tissue with sive plates.
(h) Super or corky tissue. (Lenticels).
(i) Laticiferous or milk tissue.
(j) Epidermal tissue.
(1) Stomata, water pores.
(2) Trichomes, wax, warts.

We shall first describe the vascular bundle system. This
constitutes the frame work of plants. It serves to strengthen
and also to conduct fluids utilized by plants. The cells com-
posing it generally have thickened walls and are- much
elongated in the direction of growth. The ducts or vessels
constitutes the xylem or woody portion of the vascular bundle,
the remainder consists of comparatively soft walled cells
called phlam. ‘The whole bundle is separated from the sur-
rounding tissue by a sheath made up of cells having their
walls thickened (xylem).

There are three kinds of vascular bundles according to
the arrangement of the xylem and phloem, namely, collateral,

92 VEGETABLE HISTOLOGY.

concentric and radical. In the collateral the xylem and
phloem are placed side by side, the xylem toward the interior
and phleem toward the exterior. Sometimes there is but one
mass of xylem to two of phlem. This is called a bi-collater-
al bundle. When the growing line is between the xylem and
phloem as in woody dicotyledons, thus causing the bundle to
grow in thickness it is called an open collateral bundle.
When the bundle soon reaches a definite size, as in most
monocotyledons, it is called a closed collateral bundle. The
concentric vas. bundle has either xylem or phloem located
centrally and surrounded by the other. Sometimes the xylem
is located centrally asin ferns. In many of the monocoty-
ledons the reverse is true.

In the radical vascular bundle the xylem tissues or plates
are arranged radially and separated from each other by
phlem. The whole is surrounded by a bundle sheath.
Sometimes the xylem plates meet in the center and sometimes
they are connected by a pithy central cylinder of parenchy-
ma.

The common corn stalk is a good object in which to
study the closed vascular bundle. Cut the stalk across at the
internode. The vascular bundles can be seen by the naked
eye as dots distributed through the stalk. This is a peculiar-
ity of the monocotyledons. Now make a thin cross section
and stain with chloriodide of zinc and examine first with low
power. The sheath, 6 in fig. 1, consists of lignified paren-
chyma cells. (Fig. 1 shows only one bundle.) These take a
red-brown stain. |

VEGETABLE HISTOLOGY. 93

| Or OF
a GQ aXexec i Sie.

Vi \ é r a \@; a
ape Os ey

ae ae
o23e™
y (EF

VASCULAR BUNDLE OF CORN STALK.

1, Pitted vessels ; 2, ringed vessels ; 3, intercellular passage; 4,

parenchyma; 5, reticulated cells; 6, sheath or endoderm ; 7, sive
plate ; 8, conducting cells. x 140.

The intercellular spaces, as at 83, may be formed by two
ways, either by the rupturing of cells or by their separation
from each other. The first may be called the ‘‘lysignian”’
and the second the ‘‘schizoginian”’ method. The ring vessels
are the first elements formed in the vascular system. 1, rep-
resents pitted vessels. Sometimes a projection is seen on the
inner wall of these vessels, it is all that remains of the divi-
sion wall between the cells. Surrounding these ringed and
pitted vessels are reticulated, thin walled cells, 5, these take
a yellow-brown stain. The various vessels constitute the

th
ee) 3 Er eos
# EER er ee PN
Sd oe Q ue oa:

xylem portion of the bundle.
The remaining portion containing the sive tubes, 7,
and conducting cells, 8, is called the bast or phloem portion

t or es
eGR ce
be. -

94 VEGETABLE HISTOLOGY.

of the bundle. This takes a distinct violet stain with chlorio-
dide of zinc. Sive tubes are never wanting. They are some-
what large, long, thin-walled cells whose partition walls are
perforated. Since the cells are quite long a cross section
may show but few of these perforated cell walls, called sive
plates. Notice that the xylem portion of bundle is toward
the interior of stem and phloem toward exterior. Also to-
ward outer side of stem the vascular bundles are more nu-
merous and the intercellular passages are no longer found
and the sheath is very much poe Sometimes several
bundles. unite laterally. .
After having carefully studied the vascular bundles nexty,

examine the epidermis. Just beneath the extreme outer layer

which contains the stomata is found a stout ring of ligneous —
(xylem, woody) tissue, this takes the same stain as the bundle
sheath. The vas. bundles with their sheaths are so placed as
to give the greatest possible strength to the stem. “om con-
stitute a system of compound pillars.

Now make longitudinal sections, both radial and tang-

ential. A radial section is made by cutting through circum:

ference and center of stem: a tangential section is made in |
any direction excep.ing through or toward center. Fig. 2
represents a portion of vascular bundle of Zea mays. The

Mth jl

We 4, o® @
= , | OO
Y

ee, L

tome ——_ OL, |
Y
q,

WIL L

ZZ. —
Uh P

Fitlin (n ies Leal

LONGITUDINAL SECTION OF ZEA MAYS.

VEGETABLE HISTOLOGY. 95

numberings are the same asin fig. 1. 4 is the parenchyma ;
6, the sheath whose cells are generally more elongated than
those shown in cut. 9, isa pitted vessel. Study carefully
the sive tubes 7. 10, represents a sive plate; 11, a mucil-
age string found in all sive tubes. Sive tissue coustitutes the
nerve system of plants; it plays an important part in the
irritable movements of piants as shown by the investigations
of Frank and others. Stain both transverse and longitudinal
sections with coralline. This is an excellent stain to bring
out the walls of vessels and rings. It stains xylem and
phicem different tints; xylem a bright coralline red and
phleem arose color. Tinct. of iodine stains ligneous tissue
quite readily but does not stain bast fibres It will also show
whether starch be present.

Next make a cross section of outer part of cucumber
stem. If you are lucky the section will show alli the struc-
tures shown in fig. 3. More likely, however, you will find
it necessary to make several sections before all the different
tissues can be found. — Use the same stains used in the corn
stalk sections. 1, represents the epidermis consisting of one
layer of cells devoid of chlorophyll; 2, is the collenchyma
layer made up of thick angled cells. The cells themselves
are prismatic in form. Collenchymais always found in close
proximity to epidermis.

It serves principally to give strength and resistance to
the outer portion of stem. Sometimes it forms a continuous
ring beneath the epidermis, sometimes only in bands as in
the stem of Yellow Dock for example. The lines of de-
marcation between the different,tissues are not so well marked
as a rule as shown in the figure. 3, represents chlorophyll
bearing rind parenchyma. 4, is sclerenchyma tissue. The
walls of its cells are very much thickened. e, in fig. 4, repre-

The student is expected to make careful drawings of what he
sees under the microscope. Use hard lead pencils on good unruled

paper.

o6 VEGETABLE HISTOLOGY.

Ripe

ea
[peas

A

tc

SECTION OF PART OF CUCUMBER STEM.

1, Epidermis ; 2, collenchyma; 3, rind parenchyma; 4, scleren-
chyma; 5, parenchym2; 6, trichomes (hair cells); 7, wart; 8, en-
larged hair cell showing protoplasmic movement, a, chromato-

phores, b, nucleus, c, protoplasmic strings, arrows indicate direction

of protoplasmic current; 9, air space beneath stomata; 10, stoma,
guard cells ; B, surface view of stoma. |

sents typical sclerenchyma cells as found in the shell of nuts,
here the cell cavity is almost obliterated. 5, is the true par-
enchyma consisting of large thin walled cells. 6, shows two
hair cells (trichomes), one has a pointed end the other
knobbed. These hair cells are very numerous in some plants
and are quite characteristic in certain orders and families. 7,
is a warty growth on the epidermis, they are generally ab-
normal developments produced by some irritation. 8, is an
enlarged hair cell to show the streaming motion in vegetable

er

VEGETABLE HISTOLOGY. 97

protoplasm. To study this use a}inch obj. and B ocular.
This motion can only be studied while the hair cells are alive.
It is very interesting to study this movement in protoplasm
since it gives ocular proof that it has the power of motion.
The only reasonable tlieory to account for this motion is Ber-
thold’s based on chemism as already explained. The arrows
indicate the direction of currents bat these directions are not
fixed, they may change and the currents flow in opposite di-
rections. Study these movements in hair cells of Primrose
and other plants. 9, is an air space found bepeath all
stomata. The two guard cells, 10, are moditied epidermal
cells. They, however, contair. chlorophyll and an elongated
clear nucleus. ‘Their function is to regulate the evaporation
of moisture from plants. Stomata are structures peculiar to
the under side of leaves, but are also found less abundantly
on upper side and on stem, ‘petiole and other parts of plauts.
All the structures in fig. 2, are to be studied in other plants
and compared with that of the cncumber. Water pores are
found in many plants. They resemble stomata somewhat
but differ from them in the fact that the guard cells are im-
movable and the opening therefore is constant in size, also
it is found that water instead of gas oozes from them. They
are found at the extremities of veins near the upper margin
of leaves.

In fig. 3, the rind parenchyma 3, should be represented
as extending to the epidermis wherever the stomata are found,
Often it is found that the rind parenchyma cells just beneath
the stomata begin to divide into oblong cells ; this division
extends over into the adjoining collenchyma. Soon a menis-
cus shaped layer of cells is formed called the cambium of
lenticel. From this cambium are developed oblong, thin-
walled, corky cells without chlorophyll. Finally these be-
come so numerous as to rupture the epidermis at the stomata.
These structures are called lenticels and appear to the
naked eye as whitish spots distributed over the bark of

/

98 | VEGETABLE HISTOLOGY.

Sambucus niger for instance. To study these make careful
surface and radial sections of these white spots and mount in
water. Look for the cambium and superimposed loosely |
connected corky cells protruding through the rupture in the
epidermis. The spaces between the loosely connected. cells
are filled with air thus admitting it to the inner tissue of the
stem. Lenticels thus takes the place of stomata in the older
stem where cork formation has begun.

True cork tissues can be studied in the bark of many
plants. Make a cross section of a small stem of Quercus of
any cork bearing stem.

a, epidermis ; b, cork cells ; c, cork cambium ; d, rind parenchy-
ma; e, typical sclerenchyma cells; f and g, method of forming
laticiferous tubes; h, calcium oxalate crystals; a, b, c, d, e, tip of
fern rootlet; x 180.

The cork cells are formed from the cork cambium shown
at c, fig. 4.. The youngest cork ceils are colorless, the older
yellow, and the oldest yellow-brown. Chloriodide of zine
stains them a yellow-brown, the younger darker than the.

VEGETABLE HISTOLOGY. 99

older. There are no intercellular spaces; cells appear rec-
tangular, filled with air. Cork is also formed over the sur-
face of wounds there serving to prevent the escape of cell
sap. Cork is formed from collenchyma. c¢ and upper layer
of b in fig. 4, represents the under and upper parts of origin-
al collenchyma cells. The layer of cork cells just beneath
- the epidermis is called the ‘‘ phelloderm,” and the cork cam-
bium is generally called the ‘‘ phellogen.”’” Make a section
through a this year’s stem of Abes rubrum in which cork
formation has just begun. In it youcan seen the first forma-
tion of the phelloderm from the upper original layer of col-
lenchyma. |

Many plants when wounded give out a milky fluid. It
is only nalky so far as consistency is concerned ; it may differ
greatly in color and chemical composition in the different
plants. This milky duid is contained in a special tissue, the
laticiferous tissue. This tissue is mostly found in the true
parenchyma, especially on the sides of vascular bundles.
Two kinds of milk tubes are distinguished, simple and com-
plex. Inthe simple variety the tube consists of a single
much elongated sometimes branching cell as in the Euphor-
bias. The complex milk tube is formed by the coalescence
of many cells as shown at f and g in fig. 4. This variety
occurs in the Dandelion. Make longitudinal sections to study
milk tubes. Ath, fig. 4, are shown a few oxalate of calcium
crystals. These are quite common though others may found.

Tracheids are intermediate in structure between lignin
cells and ducts. They differ from wood in having their
walls less thickened, thus giving rise to pitted, spiral or
ring like markings. Pitted tracheids are peculiar to pines.
Make a longitudinal section of young stem, soak in alcohol
to dissolve resin, and mount in water or dilute alcohol.
Tracheids differ from ducts in that they do not become con-
fluent end to end to form tubes; each tracheid consists of a
single elongated cell. Carefully study the pitted tracheids in

100 VEGETABLE HISTOLOGY.

both cross and longitudinal sections of pine stem. The pits
appear as circular dots on the cell wall in the longitudinal
section, facing toward the radial surface of section.

This article on Vegetable Histology is only intended to
give the student a start in the study of plant structure. Suf-
ficient has been indicated to enable the student to study tissues
in different plants and make comparisons.

Fi NS e

i ee 5-34

a SA SESE IE ed) ee ee 5—6
MEME HIIStOLY.-..---.--- 225. 22 see. aN Eat a pee ee 5--6
Meemyrics.......... ae ee ES eel RS 2 1S a 7
RN i oe ae ae ky &. phon ein 7-10
SC Bo ess I ee ae ie
ce SIRI aie Si re oe 7
ha SAIS Se ae as eR 10
(7 sec A ee er Sine een nan 10
MEE ATCHIGR Se re 10
EY EG te ee a 10
TE re OLN gc 10
TET eg en oe aie ace) Rie ee a a 12-20
1 Refraction by plane surfaces ............ 13

2° Refraction by inclined surfaces .......... 14
mex G1 heiraction.-.<.....:.......-.. 13-43

0 DGS ay es ee a 12
SE CRISS aE gt Lae re 13
meerprie Center of Lens... 1s cee we 15-16

5° Conjugate Foci........ Re ck er nar at ge 16
MITTAL GOR se na ead gee vc oe 17
Bemersiot LLCNsGS:..... 2. 62 ac va do ee ck se 17
Seeeeerircal tT roblems. ... 2.2... -5p hss eee... 20
rs) ee al si widely od we 90-34
RTE SS SRT CP cae i oe 31-99
Eeeannope Maonifiers....:..... ..2....... 21
MEMO LONSCS) ls. oe ici ee eek: 2]
SLE ee ie ae ta eee 21

NRL OL ESTERS a a nO 99
=<ompound Microscopes... .......si.......: 29-34.
Re AYER, codes renee) ee AN aad Bie IY ast 29-392

ii INDEX.

Stand 2 tee a. Se 22-33
1° Jackson Medel. 252°... ae 29 -
oF Ross Miedel’. Se. ae ype

2? Obreetrmea Nae Beet Ae 5... 9 ee 24
1*® onstereriom Seo Bom ee ee

1” Wenham’s, Formula’ 22.* .:.. sae 27
? Other Combinahons 4.355% 2. ae 27
Of AMOePUre .f os os Sheet ee ee . oes
Air Angle: 2... ge 6 See 26
Numeriéales fo... a eee 7
SP OWEF Va Ue ce ks ee 26
Pgh ra ae Sr 26
GOW S20 ese oS oS ee a) Ee See 26
4° Immersion Objectives’... 22) 5.5. 7a 26
1’ Homogeneous ......... Jets oe eee 26
2 Onl Premercion . 0) oY oe 26
5° F roperies oe Sc, A eee ... 28-29
¥ Working ‘Distunee . 0". 552 eee 28
2' Defining: Power . 0-50 +e eee 98
3’ Freedom from Aberration......... 29
4’ Penetrating Power. .:',/: 2 aves 29
5" Resolving Power 2. 3.0.0. eae 2

3” Evyepieces.or Oentars... 220.5% ... ote
J aoyehenian. (foc ee eee a
oY Achromatic... oo a. eee eee 28
BF Sg 2 ee a ee 27

4° A jaetrnienta ties. iis yh oe ee 30
| Midge sib | ORDA ap 0 POE ee ead 30
eo” Ooarge 40k ieee ee ee 30

Be tae) oe ene eu. ae ao,

G. pubstawe. 6. Uh eee ol 30-31

T Diaphragm)... occ. Ae 30
PAY ReOOL oe O20 Cee ae 30
perlena 8 ey ee ea ahs 4 ea eis Ds 30

Sor hs OU ee 2 30
Llane... Gea ee 30

INDEX. | iii

ee A CCESHOMCS 22 ho 22. de ele ee. ale
NECRURUNMNLE tana Oe ee yi ys Fal 1 29
Mme ICGCH. 28a 8 2 a ee eo 31
POMUOMM@eNISOFS .. 2... we oe ee. Deas ok
PRESMCOCLOTS. . 22 Ss eee te. wre ae
5° Microscope Tables ........ ae ia nae 31
memeicroscope Lamps). 2 2...) 6... : 31
SNMP COMECEETS eo ayo bea at See he. pie 22:
re PL CIC «bos orks fo eo A 32

3* Use and Care of Microscope............. 33-34

I ile a poke este dn ce wlals Uh Me 35-81
DEE IEIOLOOY 2 ee a 35-40
Bemececreiry Material... 2... 26.2.2. TY by ta a" 41-44
MMM thing 6 ada kw) eh Caer) Ses de 44-46
UNIS Ese Se ae Oy RES I ea 44
LE aaa eee es gl 44
1 I US Reet eae a pn 44
le ESSERE REL tht a aes ees SE EO Sr OnE Oe 44
eco nemo oe Bee aed ae ak 46-48
IC C2 oe ry NE ee hel, 48-50
I i 23's a Pa ae 58-60
NCES ot Fr oo OU ene 61-62
SER ICMIBCICS 54) Pati e eee ie eee ee 63-64
I hte ee katie Ss Sa Suse in cet Sig es 63
EE te arte et ee Ca ee | 63-64
naeY CIFCHIATION sok e 2 te ee we es e 64
Semerary Monts... - 2.1.0. eee ce ele. 65
See roparations...../...20. 05.5.5... 66-68
hee @eperatons for Microtome~;>.............. 68-72
MEA DIG LISSUC 2... oe ye eee ee (2-74
EN ee ie eee
INST. Sy RR ARR a glo a as se 74-75
IN ee Cet hc yi ipsa eae yin 'y "asco ogo eb 0-0 76-79
I IRUE SS CUE HOA rg) ee a te 79-81

EG YEE is thicl ty Aiea ese ON ti Af
RI SER a JE ar ee 82-83 ©

lv INDEX.

Megetable Fistolagy 2. vse 0). : ee ae
1’ Cell structnres. eke ite oa Re
2° Micellis:: 0s hi44 cae Ae 2 a a ' ce
3" Protoplasmt $4.3 sues eile bas Shes | or

4! Zell. Grannla: alee eo on ee ee. | eee

5 Gell ‘division. 22520 5. 2. Seale ee ae
G" ‘Tissues 2k ee ck Os a el OP
1° Meristematies os... <0.) 2-2 Se ee
1° Dermatogen.....02 Jo ak ee
® Pertblem. . eco nrugek- oe va a. ig aa
S FICLOME. 7.27 ue HPs Via een rena cs aaah’
2 Widatiire: brow a ctr ee
1° 'V ascularttissnes:<..:. 5. oa ke eee
2 Parenchymar on bps vay eee oe
oe Collenehynrige wees are: ae
4° Bolereieh yaar oie ie hf Soa |
y° Lee. See ss Bei olden et os
6° Tracherdsyann eels tet sn ee

10° Epidermal -tiemme: 2 0.025... ~2

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