Sentence:  The "general character of muscle" may well be studied by examining a piece of beef. It is reddish in colour, but this is due to the presence of blood, which circulates through every part of it. If we steep a piece of beef for a very long time in cold water, a large proportion of blood oozes out and <WSD>tinges</WSD> the water, leaving the flesh or muscle of a pale whitish colour. 
Meaning of the word marked with <WSD> tags:  To add a small amount of colour; to tint;  to add a small amount of some other thing.