"Then you should say what you mean," the March Hare went on. "I do," Alice hastily replied, "at least—at least, I mean what I say—that's the same thing, you know." "Not the same thing a bit," said the Hatter. "You might just as well say that 'I see what I eat' is the same thing as 'I eat what I see'!" (From Lewis Carrol's Alice in Wonderland).
In a similar vein you might just as well say that knowledge of the indication for fluid therapy is the same thing as an indication of knowledge about fluid therapy. That, however, is "not the same thing a bit."
Dr. Darrow, a pioneer and eminent authority in the field of electrolyte and water metabolism, writing in clear, concise, expository English demonstrates this point exceedingly well. A thorough discussion of the chemical principles, body composition of fluids, and renal and circulatory factors precedes a