It is the absence of this idea of competition among hypotheses that vitiates Mr Witherow's criticism. He does not say how the amyl nitrite hypothesis meets the difficulties he mentions better than the viral hypothesis does. He claims that predictions of the progress of the epidemic based on this hypothesis 'did not come true'. Were predictions based on the amyl nitrite hypothesis any more accurate?
What is far worse, however, is that he ignores the major features of the disease - above all, its transmission to recipients of blood and blood products - which have a simple explanation if Aids is caused by HIV infection but which are absolutely baffling if it is not.
ANDREW F. W. COULSON
Musselburgh, MidlothianReuse content