The Ralph knife in practice

Publisher Website
Google Scholar
Abstract
SUMMARY: Long edge glass knives, ‘Ralph knives’, were produced in an LKB Histo KnifeMaker. The edge angles were measured by light microscopy; depending on the breaking conditions the angles varied between 12° and 58°, as measured close to the edge in the mid‐portion of the knives. Hackle marks were more common in the left portion of the edge than in the middle and right portions.Some of the knives were used for cutting sections from urinary bladder tumours embedded in paraffin or in glycol methacrylate. Following microtomy the sections were allowed to stretch on a water surface; this procedure resulted in an increased width of the plastic sections, whereas the paraffin sections were not affected. The compression of the whole sections averaged 15% in the paraffin sections and 11% in the plastic sections; in both cases the compression factors were positively correlated to the angle of the knife edge. Smaller compression factors were found for the cell nuclei in the embedded tissue.