Spallanzani, a believer in preformation theory, found that he could prevent contamination by microorganisms in strongly heated infusions protected from aerial contamination, but he observed that as soon as air was allowed to enter the flask, microorganisms proliferated. He was one of the first to dispute the doctrine of spontaneous generation. Digital facsimile from Google Books at this link.

In this preliminary to a larger work on regeneration which was never published, Spallanzani described regenerative capacities of remarkable complexity and repetitiveness in the land snail, salamander and toad and frog, establishing the general law that an inverse ratio obtains between the regenerative capacity and age of the individual. Digital facsimile from Google Books at this link. English translation as An essay on animal reproductions (London, 1769). Digital facsimile of the English translation from Google Books at this link.

In this response to Haller's Deux mémoires sur le mouvement du sang (1756) (No. 11607) Spallanzani outlined his own findings on the action of the heart upon the blood vessels. "Haller's microscopic observations of blood movements had been made by refracted light on midium-sized vessels in the isolated mesontery of the frog. Splallanzani, using P. Lyonet's novel dissecting apparatus, conducted his observations mostly in a darkened room with reflected light from sunbeams impinging upon exposed parts of the aquatic salamander. He systematically noted now the cardiac systolic force motivated the blood circulation. The rhythmic inequality of blood flow in the aorta and large vessels disappeared in medium and small arteries, becoming regular and uniform. The velocity diminished in the smaller vessels, but sinuosities did not retard the flow. In the smallest vessels, individual red corpuscles negoiated acute angles and folds by elastically changing shape. The blood velocity in the venous sytem increased as the caliber of the vessels enlarged. Haller responed to the many amplifications and corrections of his work by securing Spallanzati's election to the Royal Society of Sciences of Gottingen" (Dolman, DSB 12, 553).

 Digital facsimile from Google Books at this link.

In four memoirs on the dynamics of the circulatory system  resulting from 337 experiments recorded in this workSpallanzani studied the role of the circulation in every stage from embryo to adult, and it was through his researches on the vascular system in the umbilical cords of embryo chicks that he first established the existence of arteriovenous anastomoses in warm-blooded animals. He also investigated the effects on the circulatory system of growth, gravity, and the consequences of wounds, as well as the changes affected in the failing circulation of dying animals. He determined that the arterial pulse was causedb y lateral pressure upon the arterial wall from cardiac impulsions conveyed by the blood column.

Digital facsimile of the 1773 edition from Biodiversity Heritage Library at this link.

Translated into English as Experiments upon the circulation of the blood, throughout the vascular system: On languid circulation: On  the motion of the blood, independent of the action of the heart: And on the pulsations of the arteries. With notes, and a sketch of the literary life of the author. By J. Tourdes. Translated into English, and illustrated with additional notes by R. Hall. London, 1801. Digital facsimile of the English translation from Google Books at this link.

Later refutation of the theory of spontaneous generation. Spallanzani’s conclusions were similar to those expressed by Pasteur nearly a century later. His collected works were published in Milan, 2 vols., 1932-33. English translation as Dissertations relative to the natural history of animals and vegetables. 2 vols., London, 1784. Digital facsimile of the "new edition, corrected and enlarged" (1789) from the Internet Archive at this link.

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.

Records on pp. 80-104 Spallanzani's work on the torpedo. In the 1780's Spallanzani turned to marine biology, making several trips to the Mediterranean region. On his visit to Portovenere in 1783 "he instituted the first marine zoologial laboratory. . . . He refuted the claim that the torpedo fish was attracted by magnets, intrepidly showing that its greatest shock was delivered when the fish was laid on a glass plate. Excising the heart did not lessen the shock until the circulation began to fail "(DSB).

Spallanzani's experimental data laid the groundwork for modern conceptions of respiratory physiology. In concluding that the blood transported carbon dioxide as a product of tissue oxidation, Spallanzani discovered parenchymatous respiration--usually accredited to the biochemist Liebig half a century later. Spallanzani demonstrated that the tissues consume oxygen and give off carbon dioxide.

Digital facsimile from Google Books at this link.

Digital facsimiles from the Internet Archive at this link.

Includes the correspondence and previously unpublished manuscripts. A description of this set is available from the publisher at this link.