The limitation as to quarterly examination is useful to meet conditions, on the one hand, where special incidence calls for increased safeguards; and, on the other, relaxation, by reason of adoption of special processes or measures lessening risk. Thus, in a yarn-dyeing factory, in consequence of occurrence of six cases within five months, a weekly instead of a quarterly examination was prescribed. After eight months, as no further cases were reported, a monthly examination was substituted for the weekly, and eventually, with continued absence of illness, the normal quarterly examination was resumed. An appointed time for the surgeon’s attendance at the factory has been found necessary, because, in conformity with the literal wording of the regulation, the occupier should not continue to employ a worker who, for one reason or another, has not been examined by the surgeon during the prescribed interval. With knowledge of the date and hour posted in a conspicuous place in the factory, excuse for absence becomes difficult. Alteration by the surgeon of his appointed time should, whenever possible, be given beforehand. Surgeons in the past frequently made examination of the persons employed with the view of taking them unawares, and so of precluding special preparation beforehand--a practice which had its advantages; but they are outweighed by the hardship inflicted on workers who were unavoidably absent, as, for example, night-workers. A health register is supplied to all occupiers where periodical medical examination is enjoined, the headings of which and manner of entry are indicated later on in this chapter. The objects which the surgeon should have in mind in making his examination are: 1. To prevent lead poisoning and minimize lead absorption. 2. To obtain information for the occupier and Inspector of Factories of the relative danger of one process and another with a view to adoption of remedial measures.