A complete treatise on artificial fish-breeding: including the reports on the subject made to the French academy and the French government; and particulars of the discovery as pursued in England

Estimation of colloidal material in soils by adsorption /

“…The quantity of colloidal material present in these fine and coarse fractions was estimated with the petrographic microscope. The details and accuracy of the method have been described by Fry in another publication (13).…”

“…In other soils examined, however, the unextracted colloid was 60 to 100 per cent as adsorptive for all three substances-dye, water, and ammonia-as the extracted material. Errors induced by the different adsorptive capacities of the extractable and unextractable colloids are reduced by the fact that the unextractable colloid usually constitutes only about one-half of the total colloidal material (Fry,13). The unextracted colloid as a rule is more nearly like the extracted colloid in its adsorptive capacity for ammonia than in its adsorptive capacity for dye or water.…”

“…However, the adsorption ratios of the fine and coarse fractions, adsorption per gram of fraction adsorption per gram of extracted colloid will, other things being equal, show the absolute quantities of colloid in the fractions in proportion as the adsorptive capacities of the extracted and unextracted colloids are alike. Now it is possible to determine the quantities of colloid in the fine and coarse fractions by microscopical observation with considerable accuracy (Fry,13). Hence a comparison of the quantities of colloid found by microscopical observation with the quantities indicated by the adsorption ratios will show approximately the relative adsorptive capacities of the extracted and unextracted colloidal materials.…”

“…Fortunately it was found possible to determine the total quantity of colloidal material in the soil by a method entirely independent of adsorption determinations (Fry,13). The method seems to be accurate within a few per cent; hence a direct comparison can be made of the relative accuracies with which the dye, water, and ammonia adsorption ratios re-present the quantity of colloidal material in the soil.…”

Classification and Treatment of Hereditary Corneal Dystrophies

“…4. Primary Calcareous Degeneration of Axenfeld.-Of this form, which accord¬ ing to Walsh and Howard (1947) may affect the conjunctiva and the cornea, no familial cases are known.…”