MEDLARS Tape

February 15, 1966

Dr. Frank 8B. Rogers

Librarian

University of Colorado Medical Center
4200 East Ninth Avenue

Denver, Colorado 80220

Dear Brad:

I have no actual record of having acknowledged your letter of December 15 and
the useful bibliographic material that went along with it. In fact, none of
the items had actual concrete information on seasonal cycles in twin births,
but one or two of the articles had more general relationship to seasonality
and were of interest to me, Meanwhile more analysis of somewhat larger files
of the data that we had here indicated that the discrepancy that we believed
to be present is probably not real. In fact there is a trap for the unwary in
the statistical analysis, since the proper base for the comparison is the num-
ber of confinements rather than the number of children delivered, if any of the
usual statistical tests are to be applied.

I have also, as you recommended, been in touch with Miss Darling at UCLA, but
apparently they are still some way from being in actual production. May I
impose on you again for another request which one of my colleagues has put to
me with some urgency? This would be for any information whatever that could
bear on the genetic variation in men or experimental animals that influences
the metabolism of catecholamines. This would include such important compounds
as adrenalin (epinephrine), noradrenalin (norepinephrine), and some compounds
in the same genus, ¢.g., serotonin, which likewise undoubtedly have any number

of synonyms,

While I am exhausting my credit I might as well lay another item on the table
for you, that ia, any work thet pag have been done in establishing a thesaurus
of diagnostic demeriptors specifically in the field of pediatrics. This would
be intended for a guide book on terms to be used in a retrieval system on
clinical records that some of my colleagues here are interested in,

Yours cordially,

Joshua Lederberg
Professor of Genetics

PS. Since I talked to you I have had the opportunity and pleasure of getting
on to the @8Q time-sharing system at SDC in Santa Monica via a teletype link
for which T have consoles now both at home and in my office. This ig working
out very well indeed and makes a marvelous anticipatory demonstration for our
colleagues here to give them some glimpse of what the ACME facility will be
able to do for them. This facility has made it possible in rather short order
Dr. Frank B. Rogers February 15, 1966
Page 2

to implement the DENDRAL structural analyzer which I have attempted to sum-
marize in the enclosed article, At the present time the program has learned

@ very modest amount of chumistry as well as topology, and does a reasonable

job of extracting from a list such as Table 2 only the chemically most plausible
constructions. While this is not my main interest in the system I believe that
the notations may well be an effective way out of the morass of conventional
chemical notation for structural search in organic chemistry.

snl Buhl athe’