I know not what prompted me 2 years ago, on reading the booklists of the History of Science Society, to pick this paperback reprint of a book I had never heard of. It was probably the echo of the lines in Alexander Pope's Essay on Man which my father had taught me to love (Epistle 2).
Vast chain of being: which from God began Nature's ethereal, human, angel, man, Beast, bird fish, insect, what no eye can see, No glass can reach; from infinite to thee, From nature's chain whatever link you strike, Tenth or ten thousandth, break the chain alike.
And in the third Epistle of the Essay Pope pursued the idea:
Look round our world, behold the chain of love Combining all below and all above, See matter next, with various life endured, Press to one centre still, the general good, See dying vegetables life sustain, See life
Kelly M. The Great Chain of Being: A Study of the History of an Idea. Arch Intern Med. 1962;110(6):916-918. doi:10.1001/archinte.1962.03620240098022