Histamine liberation by cotton dust extracts: evidence against its causation by bacterial endotoxins.

The recently stated hypothesis that histamine liberation by cotton dust extracts is caused by endotoxins from gram-negative bacteria contained in cotton was studied experimentally in various animals. It was shown clearly that such amounts of endotoxin as were found in cotton dust did not give rise to histamine liberation which was provoked by extracts from cotton card-room dusts. Further arguments are given which testify against the endotoxin hypothesis.