Sentence:  The first or <WSD>institutionary</WSD> part, which is divided into seven books, explains the principles on which the art is founded, and may be read with pleasure even by those who would wish only to be acquainted with the theory of medicine, considered as a curious and interesting branch of natural philosophy.Webster 1913 
Meaning of the word marked with <WSD> tags:  Containing the first principles or doctrines; rudimentary.