This article aims to point out the particular theoretical approach adopted by Luigi Devoto, and by the physicians gathered around him at the Clinica del lavoro in Milan, in studying the causes and the treatment of some of the most common occupa tional diseases among the working classes in Milan at the beginning of the Twentieth Century. Our focus was placed on researches related to lung disease and lead poisoning, because through these we can understand very well the methods of investigation carried out at that time, and at the same time we can detect the broad differences between the characteristic approach of the Milan group and that of researchers from other medical centers. It is particularly relevant, in the case of lung disease, the underestimation of the peculiarities of silicosis, which was specifically recognized only with a lag. The situation was different for lead poisoning; here the results obtained by the personnel of the Clinica del lavoro were of great importance, both in the field of research carried out in its laboratories and in that of the prevention culture. PAROLE CHIAVE storia della medicina, medicina del lavoro, malattie polmonari, silicosi, intossicazioni da metalli pesanti, saturnismo.
Keywords: History of medicine, occupational medicine , lung diseases, silicosis, heavy metal poisonings , lead poisoning.