7 
E. Experiments with Eukarvotic Host-Vectors 
1. No issue with regard to these guidelines raised more comment 
than the use of SV40 DNA. Some thoughtful scientists have even 
gone so far as to suggest a complete ban on the use of SV40 DNA. 
In my view, the relatively extensive knowledge of SV40 virus 
provides us with added assurance that its use will yield further 
valuable information and, further, that sufficient sophistica- 
tion exists to ensure its safe handling under the conditions 
developed for its use in the guidelines. I believe work with 
SV40 should continue under the most careful conditions. In 
this regard, suggestions have been made that experiments such 
as those described under section 2.b. on p. 37 of the guidelines 
should be carried out under P4 conditions instead of P3 conditions 
as recommended in the guidelines. What are the committee’s 
views on this matter? 
2. It is clear from the criticisms received that a number of 
commentators were troubled by the section on plant host-vector 
systems. I am also concerned that perhaps more concentrated 
work on this section is needed. It might be best to state in 
the guidelines that the setting of containment levels for this 
type of work will be deferred until the committee can give it 
more attention, supplemented by more ad hoc consultants in this 
field. To expedite this, I have requested Dr. Stetten to 
convene a subcommittee with augmented experience in plants 
to review this section. I would appreciate the committee's 
response to this suggestion. 
F. Implementation 
Understandably less complete than other portions of the draft 
guidelines, the section on implementation has aroused the largest 
number of comments from scientific and non-scientific quarters. 
These relate particularly to extension of guidelines beyond the 
NIH-supported community, how we can assure that research not be 
paralyzed by the inflexibility of excessive administrative 
control, how opportunity for continuous evolution of the guidelines 
can be protected, and the distribution of responsibilities between 
the investigator, his institution and community, and the NIH 
and other national interests. Much of the success of these 
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