Microscopes and Accessory Apparatus Part 10

Price, when thus mounted =4.75=

[Ill.u.s.tration: Binocular Preparation Microscope.]

73. =The Binocular Preparation Microscope=, after the model of Eilhard Schulze permits the convenient use of both eyes in dissecting small anatomical and botanical preparations. It consists of two Brucke lenses, adjusted to an accurate focus.

Both tubes are moveable on a joint and are adjustable to various distances between the observers eyes. The distance of the eye from the preparation is about 250 millimetres; the field of vision is large and flat; the magnification, four diameters; lenses are adjustable to either vertical or horizontal position and may be raised and lowered on the vertical support, thumb-screws fixing them in the desired position. A rack and pinion serves as fine adjustment =24.--=

[Ill.u.s.tration: Greenough's Binocular Microscope.]

74. =Greenough's Stereoscopic Binocular Microscope.= Two microscope tubes are so arranged as to bring the same object into focus in the axis of each tube, the tubes being set at an angle to each other for this purpose. The stand is provided with rack and pinion adjustment and both draw-tubes are also regulated by a rack and pinion arrangement, so that they may be adapted to the correct distance of the observers eyes.

By interposition of prisms the image is rendered erect.

Magnification, 20 diam. Price =80.--=

74a. =Corneal-Microscope=, is designed for the examination of the interior of the eye.

=Prismtube= No. 49 with eye-piece =16.--=

=Objective= of low power permitting 2 degrees of magnification =6.--=

=Stand= on heavy base, with rack and pinion adjustment etc. =8.--= ------- =30.--=

=Apparatus for Blood Examinations.=

[Ill.u.s.tration: Micro-Spectroscope.]

75. =The Micro-Spectroscope= fits into the tube of the microscope like any ordinary eye-piece and may be fixed in any desired position by means of the thumb-screw M.

The position of the bright and dark lines of the spectrum and their respective wave lengths are ascertained by means of a scale. The flat drum A, the interior of which is shown in section, contains the slit and the comparison prism. The slit is regulated by the screws F and H. The lever T moves the comparison prism across one half of the slit. The cylinder Q above the eye-piece contains the Amici prism. At the point N of the horizontal tube RN is the micrometer scale, illuminated by the mirror O. After raising the spring- catch L the upper part of the spectroscope may be turned round the pivot K, thus allowing of the adjustment of the eye-piece =66.--=

(A full description accompanies each instrument.)

76. =Hand-Spectroscope=, Browning's, for spectroscopic examination of the blood =12.--=

76a. =Hand-Spectroscope= with comparison prism, mirror, and holder for vials =16.--=

[Ill.u.s.tration: Thoma's Haemacytometer.]

77. =Thoma's Haemacytometer= consists of an object gla.s.s with carefully constructed cell, a ground absolutely plane covergla.s.s and two pipettes for mixing the blood and saline solution used in the examinations. One of these pipettes, for estimating the number of red corpuscles is so graduated as to permit dilution of the blood 100 or 200 times as required; the other, for counting the white corpuscles (leucocytes), is graduated for dilution of the blood 10 or 20 times.

The volume contents of the pipettes are most carefully determined and the depth of the cell is established by accurate micrometric measurement, thus permitting very exact observations by means of this instrument.

(A full description with each instrument) =14.50=

78. =Mixing-Pipette for white corpuscles= =3.60=

79. =Mixing-Pipette for red corpuscles= =3.60=

80. =Thoma counting chamber, with covergla.s.s= =5.75=

81. =Turck counting chamber with covergla.s.s= =7.25=

[Ill.u.s.tration: Counting chamber after Thoma after Turck.]

[Ill.u.s.tration: Ehrlich's Eye-piece.]

82. =Ehrlich's Eye-piece= is provided with a diaphragm having a square opening, the size of which is regulated by a small lever.

This eye-piece is designed to facilitate the estimation of the relative numbers of red and white blood corpuscles in dry preparations.

Full directions accompany each instrument =12.--=

82a. =Apparatus= for the clinical determination of the alcalinity of the blood, after Prof. C. S. Engel.

The following parts compose the apparatus:

1) a capillary pipette so graduated as to permit the dilution of 0,05 cc. blood from the finger, up to 5 cc.

with distilled water.

2) a beaker, for the reception of the diluted blood.

3) a burette mounted on stand, capacity 10 cc. Full directions accompany each outfit. Price in box =8.--=

=Micrometers.=

[Ill.u.s.tration: Screw Micrometer Eye-piece.]

83. =Screw-micrometer eye-piece= for accurate measurement of large objects. Between the eye lens and the collecting lens of a Huyghenian ocular there is a millimeter scale etched on gla.s.s, above which is a moveable indicator whose position is controlled by a micrometer screw to which a graduated drum is attached.

The value of each graduation on the drum (about 1/20 of the micrometer value of the objective) must be determined for each combination of ocular and objective by means of the stage micrometer. The eye lens of the ocular is moveable to permit accurate focus upon the scale. The apparatus slips into the tube of the microscope like any ordinary eye-piece and is fixed in position by a thumb-screw at the side =20.--=

84. =Micrometer eye-piece.= The mount unscrews in the centre to permit the introduction of the micrometer scale. The eye lens is moveable to permit of accurate focus on the scale =4.--=

85. =Gla.s.s-Micrometer for the eye-piece=, to drop on the diaphragm of the eye-piece. Scale of 5 mm divided into 100 parts =2.50=

86. =The same=, 10 mm divided into 100 parts =2.--=

87. =Stage-Micrometer=, 1 mm divided into 100 parts etched on gla.s.s =3.75=

88. =Stage-Micrometer=, photographed on gla.s.s, 2 mm divided into 200 parts =1.40=

89. =Eye-piece Micrometer=, divided into squares for counting scattered objects in the field. Mounted.

Distance between the lines 0,5 mm =2.--=

90. =Gla.s.s slide with cell= 2/10 mm deep, with ocular micrometer No. 89, in box =3.25=