Read it through once

Some pretend to see a difference between the Greenland whale of the English and the right whale of the Americans. But they precisely agree in all their grand features; nor has there yet been presented a single determinate fact upon which to ground a radical distinction. It is by endless subdivisions based upon the most inconclusive differences, that some departments of natural history become so repellingly intricate. The right whale will be elsewhere treated of at some length, with reference to elucidating the sperm whale.