HARRY ROSS

RAND MICROTOME: WELL PATTERN

When only a few thin sections are required this hand microtome, invented a long time ago by Ranvier, is extremely convenient. The tissue is embedded in paraffin, carrot, potato or pith and then placed in the well of the microtome. This is best done by cutting the supporting material into a core which will fit snugly into the well, then slicing it lengthwise and placing the tissue in this cut. If paraffin is used, a paper form is made which has the dimensions of the well, place the tissue in thin form, and pour melted but cool paraffin into the form. When hard, the paraffin will support the tissue for cutting. While designed primarily for cutting section of stems and roots, this hand microtome can be used for both animal and vegatable tissue. The feed is accurate and, by means of a micrometer screw, entirely enclosed. Each graduation has a value of about 5 microns. Tissue in size to 1/2" diameter and 2" long can be handled. After placing the tissue in the well - it is gradually raised by means of the milled head, a section may now be cut. This is repeated until a sufficient number of section are secured.

A very, very sharp razor or microtome knife is required. Adjust the thickness of sections cut so that they do not curl. Books on section cutting will give hints of how to get good sections and how these are stained.

The right figure shows a Hand Microtome, overall length about 7", which sells for about $6.00.

The left figure shows how the knife is held to cut a section with this instrument.

VERTICAL ILLUMINATOR

A simplified vertical illuminator for opaque objects such as polished metal surfaces is a very handy instrument for the microscopist to have around. With it he can see the beautiful crystaline surfaces of etched polished metals. Study of these surfaces is both instructive and interesting. A knowledge of metallography may even be of financial gain to him.

This unit is designed so that it can be screwed into the nosepiece of a standard biological microscope in place of the objective. The objective is then screwed into the lower end of the illuminator which has the standard R. M.S. screw thread.

A collimated beam of bright light is projected upon the coverglass reflector inside the body of the illuminator. This cover is rotated by means of the knob on the unit so that the light is thrown down thru the objective upon the objective. The polished surface of the object reflect light upward into the objective and an image formed of this surface in the eyepiece.

With this type of illuminator the full resolving power of the objective is employed as the cone of light from the back lens is not obstructed by mirror or prism. The plain glass reflector is mounted so that it can be readily replaced or adjusted by means of knob on the side. A lock-nut sets the reflector in place when the correct angle is found. The unit pictured on the right is made of duraluminum and sells for about $7.50.

The general arrangement of the microscope and lamp is shown on the left.