Comparative microscopy of bleached, unstained softwood tracheids including measurement of refractive index

Because of difficulty experienced with visual observation of bleached, unstained softwood tracheids, a study was initiated to determine the best microscopic system, for observation of this type of material. A comparison was made between bright-field, dark-field, polarising, phase, electron, fluorescence and interference microscopic systems. In addition, the optical characteristics of each type of microscope were studied to determine the reasons for the differences in visual results. The study was expanded to include an evaluation of the interference microscope and its use in measuring refractive index of bleached wood pulp. The interference microscope was found to give visual images superior to those obtained with any of the other systems examined and thus constitutes an important, contribution to the practice of microscopy. Inconclusive results were obtained in the evaluation of the system of measurement of refractive index by means of the interference microscope.Forestry, Faculty ofGraduat