94 
Dr. Sinsheimer. 
DR. SINSHEIMER: I would just like to make a comment about something 
that was implicit in what you said. Bob. I just feel that this document 
that we are reviewing and many of the comments that are being made carry 
us down this road of saying that the K-12 is such an enfeebled organism it 
is practically what we used to call an EK2 anyway, and so forth, and maybe 
that is true. But actually I am not personally yet convinced that it is 
true for two reasons. One, that the data supporting that is simply not 
available in the literature. Secondly, we are still, it seems to me, in a 
position where — well, the statement is made that this experiment or that 
experiment which attempted to make K-12 pathogenic did not succeed. That 
leaves you in the position of not knowing what you would have to do to make 
it pathogenic, not knowing what the defect really is. It may not be all 
that intricate, it may be that simply no one has done the right experiment. 
And until you do know what the nature of the defect is, I think it is some- 
what misleading to suggest that it would be so horribly difficult to make 
it pathogenic. It is just a logical position. 
DR. BOCK: I think my principal comment here could be even applied to 
K-12, that I believe it would be better to try to come up with objective 
criteria that describe a safe host and a safe vector in operational or 
quantitative terms, so that one could get on with the job, rather than, 
as you say, take something which so far looks so safe we haven't been 
able to find out what are the limitations. On the other hand, the number 
of experiments are by no means complete that we have tested K-12 or Chi- 
1776, for that matter, in every possible way to make it pathogenic. 
DR. FREDRICKSON: Dr. Ginsberg. 
DR. GINSBERG: I can't let Dr. Sinsheimer's statement go by without 
speaking to that rather than to Dr. Bock's statement, and that is that even 
at its best E. coli is not a very good pathogen. So trying to do what he 
says is essentially an impossibility because it just is not a very patho- 
genic organism except under very unusual circumstances. So we are asking 
almost something that isn't very likely to be found. 
DR. FREDRICKSON: Mr. Hutt. 
MR. HUTT: Again a question of clarification, Bob. You have twice 
now said that one ought to have these objective criteria. Are you pro- 
posing specific objective criteria? 
DR. BOCK: No, I am encouraging both the biological safety committee 
and the physical containment committee to try to couch their descriptions 
in terms of performance. I believe that that is possible. 
MR. HUTT: But you are not able to point to any written language that 
anyone has proposed thus far that would do that? 
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