All but one of these letters are to Charles Alston, the professor of botany at Edinburgh University, and concern medicine, botany, and science in general. They are dated between 1737 and 1750. One letter is to George Whately, dated 1778.

This microfilm contains letters and drafts of replies, memoranda, lists of plants and shrubs, observations on natural history, diary notes, extracts from reading, and recipes. There is a "Catalogue of Books given to [Friends] Publick School of Philadelphia" by Collinson dated 1749. There is a copy by Collinson of a May 16, 1560 note by Elizabeth I of a gift of old clothes to her maids of honor. A 1811 letter is from C. S. Collinson to Aylmer Bourke Lambert.