NOTES ON TECHNIC 255

HIDEO TAMATE and Yo KONDO, Department of Animal Husbandry, Faculty of Agriculture, Tohoku University, Sendai, Japan.

REFERENCES CROSSMAN. G .

SHANKLIN, M., and NASSER, T. K.

1937. A modification of Mallory’s connective tissue stain with a discussion of

Luxol fast blue combined with the periodic acid- the principles involved. Anat. Rec., 69, 33-8.

Schiff procedure for cytological staining of kidney. 1959.

Stain Techn., 34, 25760.

A SIMPLE MACROTOME FOR SOFT TISUFS

The apparatus was designed to cut uniform 1 mm slices of fresh rat brain. A simple chopping motion was superior to shearing with scissors or slicing with a knife, since chopping resulted in very little distortion of the soft tissue (see McIlwain and Buddle 1953). The inertia of fresh tissue is such that, when it is struck a sudden blow with a razor edge, little depression occurs at the site of entry of the blade. The resilience of the tissue permits cutting with negligible permanent distortion.

Chopping is performed by a clean razor blade clamped on one end of a bar (B, figure 1). At the opposite end, the bar is pivoted on a screw between two right angle brackets. The bar is held in the raised position by a simple trigger. This trigger is made from spring steel wire and passes through holes drilled in the angle brackets. When the trigger is drawn by means of the projecting loop (T, figure l), the spring and weight of the bar swing the blade into the specimen.

The sample rests on moist filter paper placed on a plastic slide, 3 x 50 x 75 mm, made of Lucite, and held in a mechanical stage. The movements of the stage are graduated in millimeters reading to tenths by verniers. After the first cut, the blade is carefully raised and cocked. The desired thickness of slice is set by lateral movement of the stage. The trigger is again released ancl a second chop is made. This sequence is repeated for as many slices as required.

The descent of the bar is limited by the stop (S, figure I ) , which is a screw and two knurled nuts padded by a bit of adhesive tape. The height of this stop and the position of the blade are both adjusted in relation to the plastic slide. Three layers of moist, hard filter paper (Whatman 50) are applied to the slide. With the blade loosely clamped and the bar in the horizontal position the stop is set so that the blade touches the paper. Next, the blade is grasped with the fingers and the cutting edge pressed into uniform contact with the paper, then clamped firmly. A chop should just cut or evenly score the uppermost piece of filter paper. This top layer should be removed when the specimen is placed in posi- tion for cutting.

The adhesion of the paper to the slide and to the tissue is important ancl de- pends on having just the right degree of wetness. Filter paper dipped in saline

Bio

tech

His

toch

em D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y H

ochs

chul

bibl

ioth

ek D

arm

stad

t on

11/2

5/14

For

pers

onal

use

onl

y.

256 STAIN TECHNOLOGY

FIG. 1. Tissue chopper with cuttingarm (E) cocked. This bar was made from a 6-inch machinist’s rule and furnishes a scale that indicates size of the apparatus. With the blade exposure shown, a sample with a cross section of 1.5 x 3 cm could be sliced. The length of the specimen cut without repositioning was about 7 cm-the travel of the mechanical stage. T. trig- ger; S, stop.

solution (or water) and lightly blotted once or twice should show no free water on its surface and should form a firm bond with the slide. This bond can be im- proved by scoring lines in the plastic slide with a scriber. A specimen should have an approximately flat surface to adhere properly to the paper although the base of a rat brain was flat enough to keep it in position. T h e whole fresh brain with the pia mater still attached was placed base down on moist filter paper. The blade and top surface of the brain were moistened to prevent the slices from sticking to the knife. Repeated cuts were made but it was not obvious that the brain had been sectioned until the slices were floated apart in saline solution. Liver and muscle also were sliced with little compression.

Acknowledgment. This work was supported by a grant from the National Institutes of Health ( B - ~ ~ ~ ~ ) . - ~ ~ & o R M I c K TEMPLETON, Department of Anat- omy, Northwestern Uniuersity Medical School, Chicago 11, Illinois.

REFERENCE MCILWAIN. H., and BUDDLE, H. L. 1953. Techniques in tissue metabolism. 1. A mechanical

chopper. Biochem. J. 53,412-20.

Bio

tech

His

toch

em D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y H

ochs

chul

bibl

ioth

ek D

arm

stad

t on

11/2

5/14

For

pers

onal

use

onl

y.