This paper is a sequel to the authoress' earlier 'A grammatical study of infinitival figura etymologica'; its aim is to conduct a detailed syntactic (part-of-speech-related) investigation of participial stem doublets (i.e., constructions of the 'várva vár' (look forward with impatience; -literally: wait waiting), 'kérve kér' (implore; -literally: ask asking) type). Given the fact that it is exclusively in the case of such stem doublets that 'participial adverbs of degree' are known in the relevant literature, the authoress approaches the construction at hand with a rather critical attitude. She shows to what extent the adverbial participle in such constructions meets the general requirements of that part of speech and in what ways it departs from them. She then comes to the conclusion that such forms do not meet the criteria of subordinate (hence of adverbial) constructions either semantically or syntactically. In view of the relatively infrequent occurrence of the construction, she backs up her arguments with selected examples taken from works of fiction. Finally, by analogy with 'set phrases', she suggests that a new concept, that of 'set forms', be introduced.