Document RjEee0oJE9m8b1XdJGw7KGrY8

CONCEPT AND SIGNIFICANCE 7 Environmental diseases of industrial origin present, moreover, not infre quently marked diagnostic difficulties, as an appreciable number of these dis orders may masquerade symptomatically under the disguise of known infectious diseases or are readily and often complicated by such conditions, so that the primary, occupational, etiological aspect becomes obscured. Some industrial diseases, on the other hand, exhibit symptoms simulating closely those found in certain diseases of unknown etiology (so-called "idio pathic diseases"), or are mistaken for organic changes observed with the "physiological" aging of the organism. The following examples may serve as illustrations of these points: The occupational exposure to benzol and to certain benzol derivatives may lead to the development of a great variety of hyperplastic and hypoplastic reactions of the blood and blood-forming organs resembling in many respects those caused by some infectious, endocrine, or unknown agents. Certain disorders of the central and peripheral nervous system which are elicited by contact with a great number of industrial poisons (carbon monoxide, hydrogen sulfide, carbon disulfide, chlorinated aliphatic hydrocarbons, aromatic hydrocarbons, organic and inorganic compounds of lead, mercury, arsenic, manganese, etc.) may mimic closely those accompanying infectious diseases or appearing as degenerative manifestations of unknown etiology (Baader). The inadequate knowledge as to the existence of such causal connections is the reason that the industrial factors producing nervous disturbances often remain unappreciated, resulting in the institution of ineffective therapeutic measures and in the complete omission of essential preventive procedures. The causal role which an occupational exposure to noxious gases and vapors (sulphur dioxide, nitrous oxide, etc.) as well as to various kinds of organic and inorganic dusts (manganese, soot, iron oxide, and especially silica) plays in the production of chronic inflammatory conditions of the respiratory organs, is not rarely more or less obliterated by the secondary onset of a bacterial infection, for which the industrial agent has prepared the soil. The occurrence of peptic ulcers in individuals exposed to carbon disulfide vapors is generally little considered in the diagnosis of gastric disorders. Likewise is the production of degenerative and fibrosing lesions of the liver by aliphatic chlorinated hydrocarbons, aromatic hydrocarbons, etc., not taken into account in de termining the causation of cirrhosis of the liver. A considerable number of irritative or allergic cutaneous lesions occurring among the industrially occupied, as well as among the general population, can be traced to an exposure to some of the innumer able new chemical compounds employed in industry and incorporated in articles of every-day use. These manifestations are not infrequently mistaken for bacterial or fungal infections which, however, are often superimposed upon, or activated by, the chemical agents. Apart from these medical difficulties which impair the proper advancement in the knowledge and recognition of these environmental diseases there exists a fundamental and serious lack of information concerning the biological effects exerted by many of the new synthetic compounds. While the manufacturers of such chemicals, as well as the users of new and old substances for new purposes,