May 25, 1960

Dr John 2 Platt
Cepartment of Physics
University of Bhxeago
Chicago 37, Lllinoi

Dear JohnRew

Forghve me for giving only a rather hasty answer about Salser's paper.

You are right that it does parallel some of my ow writing, and having sinned

myself, I would hardly enjoin anyone else against it. The non-distinguishability

of parasites from plasmagenes underlies the introduction of the tern "*plasmid*

(to include both). Physiol. Revs,, 32:403, 1952, I would say now that we

might distinguish a virus not by its pathogenicity, but by whether it had a ~

particular adaptation to survive outside the cell and to reenter susceptible *~

cells,- not a very fundamental eriterion, In another paper -- $54 of encl., 3

-- we struggled with the problem of defining 'creative information', we called Al
this "biologically significant information’, rather clumsily. The problem is ae

still with us; I don't think thet Salser has been able to clarify it very

mach further, however, Genetic va, 'nonegenetic! (or epigenetic) rather provoked _

me, as used by Ephrussi and Nanney; in #47 I suggested that we should simply »

distinguish 'nucletec! from non»nucleie and even epinucleic information, The | .

main polit I would stress now is that a long heteropolymer like ONA is informational.

ly dense (2 bits per nucleotide) compared to the content of most of the other

systems, generalyl bit per particle or per systen,

On the whole the paper is quite reasondble, except for the relianwe on
coacervates pp.l8 ff and membranes as primary reservoirs of replicating information
-- that is, my own sequence would put polymers first. The viewpoint is somewhat,
not startlingly, different from other contributions in the field; it is gell
weitten; 4t is not especially new, but not much in this field is, If he were
my atudent, I would give him an A in the course, but would not encourage hin
to launeh his career in scientific publication with this type of article.

I do object to the tmkakckukek titic.

Have you caught any cosmic dust? Any ideas how to? Are there any molecules
in the primary cosmic radiation? If so they might give spectacular and identifiable
events (possibly notnew being looked for) in emilsien exposures, (Presumably
any such molegules would have been torn apart long since, but what are the
quantative inferences?)

3 }
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13 Jj oof Sincerely,

Man

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