To the Editor.— I am not really enlightened by Bernard Ackerman's reply to Dr Samuelson's query in the JulyArchives(111:925, 1975). If the antigens were "suspended in an aqueous solution," one immediately wonders "a solution of what?" If it was a solution of nothing or if the antigens were not in fact suspended, but dissolved, then it would have been best to come right out and say "water" instead of an aqueous solution—if water is what was meant.