3 . 
criteria, which are central to any consideration of the 
probable consequences of introducing a toxin gene into 
E. coli , were taken into consideration by the Swiss and 
German ad hoc committees, which were composed of medical 
microbiologists, and I have indicated above the conclu- 
sions at which they arrived. 
I hope these comments are of some assistance to you in 
your deliberations and I look forward to learning of 
your decision. 
Yours sincerely 
K.N. Timmis 
Professor of Biochemistry 
[ 621 ] 
