Prophylactic low-dose heparin by jet injection.

graphic deterioration, in the patient and others affected by aerosols of contaminated water in other factories2 3 no radiographic changes were evident after several years' exposure, and no functional abnormalities persisted when away from work. Furthermore, the symptoms were prominent in the early part of the week, improving while continuing at work, but recurring on return to work after an absence. This pattern is similar to the "Monday fever" of byssinosis, but differs so far as we know in the site of reaction, being predominantly bronchial in byssinosis and peripheral in "humidifier fever." The source of the antigens was identified in this case but the precise causal agent was not, and it may, as Edwards suggested, be derived from free-living amoebae.4 Awareness of this unusual pattern of reaction should allow earlier identification of its cause, although confirmation may be obtained only by systematic observations at work or by inhalation testing.