Sentence:  Evidence <WSD>is</WSD> plentiful that early and later also he has been indebted to the Gothic romancers , who deal in extravagant horror , to the symbolists writing at the end of the preceding century , and in particular to the stream-of-consciousness novelists , Henry James and James Joyce among them . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)