Sentence:  But, Wecker says, from melancholy <WSD>adust</WSD> arises one kind; from choler another, which is most brutish; from phlegm another, which is dull; and from blood another, which is the best. 
Meaning of the word marked with <WSD> tags:  Abnormally dark or over-concentrated; "associated with various states of discomfort or illness (specifically being too hot or dry)". (from 15th c.)