The reason...for...dividing his book into three parts in honor of the Holy Trinity is that there are three principal things to be looked to for the re-establishment of the health of the body — the preparatory sirup, the medicine, and good regimen.

Partitur autem totale opus ad honorem Sanctæ Trinitatis in tres libros. Nam sicut infirmanti corpori . . . . tria impertiri curamus: primo, syrupum ad præviam dispositionem; . . . . secundo, congruam medicinam quæ morbum expellat; . . . . tertio, ad conservandam sanitatem debitum vitæ regimen. . . . Sic conformiter continet liber primus dispositionem quasi syrupum, etc.