Darwin thoroughly appreciated the good work put into the index of "The Variation of Animals and Plants.")
(Darwin; thoroughly appreciated; the good work put into the index of "The Variation of Animals and Plants) (the good work; put; into the index of "The Variation of Animals and Plants)
Darwin the good work
thoroughly appreciated put
the good work put into the index of "The Variation of Animals and Plants
into the index of "The Variation of Animals and Plants