Regarding his important work on the Latin, Adler writes in the preface to the textbook: "The preparation of a text-book for the study of the Latin, similar to that edited by me, some twelve years ago, on the German, has since that time been repeatedly suggested to me … Years however elapsed before I could even think of entering on such a task, … partly because I felt, in common with many others, some hesitation to undertake the somewhat delicate part of treating a so-called dead language like a living organism … It was not until after I had completed what I considered myself bound to render, as professor of a modern language in the city of New York, that I could give the question a serious consideration."
Melville wrote of that encounter: "He is author of a formidable lexicon (German and English); in compiling which he almost ruined his health.
Melville spent many hours talking to Adler, talking of "Fixed Fate, Free will, foreknowledge and the absolute", said Melville, "his philosophy is Coleredgian [sic], he accepts the scriptures as divine, and yet leaves himself free to inquire into nature.
It was a sorry affair, a man of genius living in confinement and dying almost unmourned, Duyckinck recorded in a letter to his son George.
"Herman Melville, [F. W.] Downer with me & two others were at the funeral, and Dr. [D. Tilden] Brown of the asylum in whose face and mien you may read the secret of Adler's regard for him."
"[6] His mind became impaired during the last years of his life, and he died at Bloomingdale asylum of New York City, on August 24, 1868.