In some regions of scales the aligned portions of microtubules trace out a set of arclike
alignments across the fibroblast layer (Fig. 9); in others, they are oriented
straight across the layer. Phase-contrast and differential interference contrast
examinations of unfixed scales showed that the aligned collagen fibres in fibrillary
plates exhibit a similar pattern of ‘arcs’ and ‘straights’. Direct comparison between
the alignment of microtubules, and collagen fibres in the layer closest to the upper
secretory surfaces of fibroblasts, was not achieved. This was because it was not
possible to differentiate between fibres at the level in question from those at other
levels in the-fibrillary plates of scales prepared for immunofluorescence microscopy.