Cogrossi, Carlo Francesco

(b. Caravaggio, Italy, 5 July 1682; d. Crema, Italy, 13 January 1769),

medicine.

Cogrossi studied at the University of Padua, where he benefited especially from the teaching of Domenico Guglielmini, an iatrophysicist and student of Malpighi. Receiving his degree in philosophy and in medicine in 1701, Cogrossi practiced medicine, first in Padua, where he also dedicated himself “to the anatomical dissection of sickly corpses of that hospital” and attended the courses of B. Ramazzini and A. Vallisnieri (to whom Cogrossi dedicated his major work). He then practiced in Venice and Crema. He was called to a chair of medicine at the University of Padua and began his teaching on 19 January 1721 with the oration “Pro medicorum virtute adversus fortunam medicam,” In 1733 he went into retirement for reasons of health; he withdrew to Crema, where he maintained a modest private practice.

Cogrossi’s most important work is the Nuova idea del male contagioso de’ buoi, which appeared in Milan in 1714 and constitutes a clear formulation of the “contagium vivum seu animatum,” based on some fundamental achievements of the seventeenth century, such as the introduction of the microscope, the negation of the theory of spontaneous generation of insects, the studies of parasitism, the discovery of the microbiological world, and the acarid etiology of mange. The starting point of the Nuova idea was furnished to Cogrossi by an outbreak of cattle plague that wreaked havoc in Italy from the summer of 1711 to 1714.

The acarid etiology of mange brought parasitism to the limits of visibility of the naked eye, explaining not only the cause and the cure but also the mechanism of contagion. Cogrossi conjectured that parasitism might occur at the microscopic level; he thought that beings invisible to the naked eye—Leeuwan-hoek’s microorganisms—could be the cause of highly contagious diseases, thereby accounting for the ease with which diseases are transmitted from man to man until they acquire the actual physiognomy of epidemics.

The living nature of the infection permits an explanation of some fundamental characteristics of contagious diseases; the receptivity of one animal species and the immunity of another to a specific infection; the susceptibility of certain individuals of the receptive species and the immunity of other individuals of the same species; and the susceptibility of a people or of a country and the immunity of another people or country. Concerning this immunity, the author hypothesizes that the life of the contaminating agent is dependent on the climatic conditions of the country and the hygienic habits of the people.

To rid a nation of a contagious disease, it is necessary to isolate and cure those infected, to isolate the suspect ones, and to disinfect the personal belongings of both, in order to exterminate the causative agent and its eggs. An epidemic that has been put down can start anew if the pathogenic germ is reintroduced to an area by an infected individual or a carrier. Renewal is much more likely if the weather conditions favor the life and the multiplication of the germ. Suggestive is the analogy with the periodicity of the invasions of grasshoppers and other insects, which are to be ascribed to their monstrous multiplication. Only the unchecked reproduction of microorganisms can explain the rapid diffusion of infection throughout vast territories, even after the importation of only one infected animal.

Cogrossi also attempts to explain how such a minuscule being can inflict illness and death on an animal the size of a steer. He rightly invokes the alterations provoked by the microorganism in the liquids and solids of the infected animal. He also speculates on the entrance routes of the infection and its transmission through the secretions and excretions of the infected animal.

BIBLIOGRAPHY

I. Original Works. Cogrossi’s major work is the Nuova idea del male contagioso de’ buoi (Milan, 1714), repr. in facs., with Eng. trans. by Dorothy M. Schullian and forward by Luigi Belloni, New Theory of the Contagious Disease Among Oxen (Milan, 1953). For a list of his minor works, see Belloni and Schullian below.

II. Secondary Literature. Works on Cogrossi are Luigi Belloni and Dorothy M. Schullian, “Una autobiografia (1735) di Carlo-Francesco Cogrossi (1682–1769) nel suo epistolario con G. M. Mazzuchelli,” in Rivista di storia delle scienze mediche e naturali45 (1954), 105–113; Luigi Belloni, “Le ‘contagium vivum’ avant Pasteur,” in Les conférences du Palais de la découverte (Paris, 1961), pp. 12–14; and “I secoli italiani della dottrina del contagio vivo,” in Simposi clinici4 (1967), liv.

Luigi Belloni