Chilton - p.3 
carefully. I would like to see considerable clarification, 
for the benefit of scientists .as well as the public, of what 
range of experiments we can now expect to find listed as 
outside the Guidelines. I support strongly the idea of ex- 
cluding many experiments which are generally regarded as safe. 
However I would hope that careful consideration will be given 
to any potential unusual hazard of recombinant DMA before 
judging it to be non-novel. 
Experimental Guidelines 
The clarification afforded by the alterations in categories 
in these revised Experimental Guidelines is excellent. The 
distinction between polypeptide toxins and other toxins is 
especially valuable. In general I support the revised Experi- 
mental Guidelines. Two items are in need of more consideration, 
and the sections dealing with them should be revised: 
1 . Containment for cloning DNA from plant pathogenic 
bacteria . The treatment of cloning experiments involving DNA 
from plant pathogenic bacteria in these revised Guidelines is 
not reasonable. The containment level required for all such 
experiments is P 3EK2 . This requirement fails to take into 
account differences in the economic importance and geographical 
domain of various bacterially caused plant diseases. A classifi- 
cation of plant pathogenic bacteria was recently proposed by 
[Appendix A — 152] 
