A study of portable vibrating tools in relation to the clinical effects which they produce.

During the recent war the clinical effects of the use of vibrating machinery have come even more to the fore than previously. This is because production methods, particularly in the aircraft industry, have required the increased use of portable grinding and riveting tools. Loriga (1911) first connected circulatory disturbances with the use of pneumatic tools, which had by then been in favour for many years. Pioneer work has been done by Alice Hamilton (1918), also by Rothstein and others (1918), and since then the historical facts have been described by several authors, notably Hunter and others (1945), Gurdjian and Walker (1945), and Dart (1946), so that a general survey of the literature would be of little advantage here. It is, nevertheless, worth while to consider certain tendencies in recent papers on the subject. In earlier years the reported series dealt with the effects of pneumatic tools of various kinds; in only one instance, that of " pounding up" machines (described by Middleton in 1930), which were used in the boot and shoe industry and which soon went out of use, was any other type of vibrating machine involved. The lesions brought about by pneumatic tools were: (a) injuries to joints; (b) injuries to muscles, fascixe, and peripheral nerves; and (c) Raynaud's phenomenon, which occurred in the hands. Of late other ways of working have produced similar clinical manifestations, and this is not surprising in view of the widespread use in modern industry of machines which produce noise and vibrations, and the demands for ever-increasing output. Telford and others (1945) discussed Raynaud's phenomenon, which occurred in those who handled portable rotary grinding tools. Agate, Druett, and Tombleson (1946) likewise reported it occurring in those who ground small iron castings against large beltdriven grinding wheels. In this instance there was