In the first patrt of this work, Della digestione dissertazione prima Spallanzani confirmed earlier doctrines of the solvent property of the gastric juice and discovered the action of the saliva in digestion. He stated that gastric juice can act outside the body and can prevent or inhibit putrefaction. He obtained gastric juice by tying a sponge on a piece of string, then allowing it to be swallowed. The second part contains Spallanzani's experimental researches on reproduction in animals and plants in which he demonstrated the role of seminal fluid in generation. The second part also includes his investigations into artifical fertilization, in which he recorded the first case of artificial insemination in a viviparous animal.

Digital facsimile from Google Books at this link. English translation, as Dissertations relative to the natural history of animals and vegetables (1784). Digital facsimile of the 1784 edition from the Internet Archive at this link.