In 1801, Erasmus Darwin advocated a hypothesis of pangenesis in the third edition of his book "Zoonomia". In 1809, Jean-Baptiste Lamarck in his "Philosophie Zoologique" put forth evidence for the idea that characteristics acquired during the lifetime of an organism, either from effects of the environment or may be passed on to the offspring. Charles Darwin first had significant contact with Lamarckism during his time at the University of Edinburgh Medical School in the late 1820s, both through Robert Edmond Grant, whom he assisted in research, and in Erasmus's journals. Darwin's first known writings on the topic of Lamarckian ideas as they related to inheritance are found in a notebook he opened in 1837, also entitled "Zoonomia". Historian Johnathan Hodge states that the theory of pangenesis itself first appeared in Darwin's notebooks in 1841.