Early in the nineteenth century, in 1826, Archbishop Richard Whately published an influential text on logic, The Elements of Logic which is credited as reviving the study of logic in English-speaking countries. It appears then that in the post-Romantic period in Germany and German-speaking countries, naturalists were not so rigid over species as was the Swiss export to America, Agassiz. To facilitate the study and knowledge of so many different bodies it is useful to give the name species to any collection of like individuals perpetuated by reproduction without change, so long as their environment does not alter enough to cause variations in their habits, character and shape. In Logic, a predicable which is considered as expressing the whole essence of the individuals of which it is affirmed. Jean Baptiste de Lamarck reiterates in the Zoological Philosophy the early view of Buffon that only individual organisms exist in nature.