(S (S (SBAR (IN Although) (S (NP (BASENP (DT the) (JJ exact) (NN nature)) (PP (IN of) (BASENP (PRPD his) (NN collapse)))) (VP (VBZ is) (ADJP (JJ unknown))))) (COMMA ,) (S (NP (BASENP (NNP Harlan)) (PRN (COMMA ,) (BASENP (DT a) (JJ full-blooded) (NNP Winnebago) (NNP Native) (NNP American)) (COMMA ,))) (VP (VBZ has) (VP (VP (VBN struggled) (PP (IN with) (BASENP (JJ post-polio) (NN syndrome)))) (PP (IN since) (BASENP (NN childhood))))))) (PERIOD .))