[Studies on cotton dust in relation to Byssinosis].

The clinical features of byssinosis which have suggested an allergic factor in its aetiology have been discussed in an earlier paper (Furness and Maitland, 1952). Prausnitz (1936) concluded, on the basis of a wheal and flare type of skin reaction elicited by injecting extracts of cotton dust, that he had demonstrated hypersensitivity specific to byssinosis and supported this view with collateral evidence. He noted also a delayed type of skin reaction which he thought was due to a non-specific toxic substance in the extract and he suggested that a direct irritant action of dust on the lungs was of primary importance in causing byssinosis. Bramwell and Ellis (1932) and Brown (1932) obtained an early type of skin reaction with extracts of cotton dust but their extracts contained histamine (Maitland, Heap, and Macdonald, 1932) and their results were of doubtful significance. That histamine or a similar substance can be extracted from cotton dust has been shown by Macdonald and Maitland (1934) and by Macdonald and Prausnitz (1936); its possible role in causing byssinosis has been discussed by Haworth and Macdonald (1937). Van Leeuwen (1932) made extracts of cotton dust which did not contain histamine. They produced an early reaction of wheal and erythema in nearly all asthmatics and a late reaction in asthmatics and in healthy people. If hypersensitivity is a major factor in byssinosis it might be possible to detect persons who had become hypersensitive before they were clinically affected and to take preventive measures. The possibility of desensitizing those with symptomatic byssinosis would also arise. The work reported here was undertaken to investigate these possibilities, but as it progressed the results of the skin tests raised doubts as to the validity of the assump-