Many years ago I read that buffalo hunters would drink the liquid out of buffalo's eyes to gross out the greenhorns and tenderfeet (people new to the West). Attached to this anecdote was a claim that all ocular fluid is potable water. Is this true?
While I don't think the source specifically stated this I believe they were talking about the Aqueous humour in apparently healthy mammals. That is the subset of animals that I'm most interested in but I'd also be interested in learning if this is generally applicable to any animal with big enough eyes.