Attempt has been made to discredit the value of Section 73 of the Factory Act, 1901, on the ground that the proportion of cases in which some degree of paralysis is present is very high as compared with the extent found by other observers. The points we have laid stress on--(1) duration of employment, (2) varying kinds and amounts of lead dust and fumes--are, we believe, quite sufficient to account for, and give value to, the figures dealt with. To them should be added another factor, though one of less account--namely, the extent to which particular muscles are used. In the case of file-cutters, for instance, there is no doubt that the cramped position of the left hand holding the chisel, and the work thrown on the right in holding the heavy mallet, determine the direction of the paralysis, especially on to the muscles of the thenar and hyperthenar eminences and of the fingers. There is, however, difficulty in deciding whether such entries on reports as “weakness of arms and legs,” “weakness of arms,” “muscular weakness,” etc., should be interpreted as incipient paralysis.[A] With a disease like lead poisoning showing marked tendency to affect the muscles supplied by the musculo-spiral and other nerves, the only safe course was to include all these terms as equivalent to partial paralysis. Table V. on p. 54 shows close parallelism for the six years. [A] During the years 1910 and 1911 cases were classified so as to distinguish definite paralysis, as far as possible, from the more indefinite terms referred to, with the result tabulated opposite. We have little doubt that in most of the cases included in columns (3) and (6) some slight degree of paresis was present.