November 7, 1958

Or. Richard T. Smith
5323 Harry Hines Blvd.
Dallas, Texas

Dear Or. Smith;

Your paper in the August number of the Journal of Experimental Medicine
has just come to my attention. t should have read it sooner but fer a
number of distractions during the last month since my return from a trip
to Europe.

1 think you can judge how delighted ! was to see your results in the
light of the enclosed speculation. In discussing this problem with a
number of my collegues, | have been rather hard put to justify in detail}
the contention that persistence of antigen was necessary for the maintain-
ence of tolerance and here you have done it beautifully! 1! will be
rather interested in your comments as to whether the proposal in the en-
closure meets the requirements of the last sentence in your paper on page
247. | might comment that the revised preposal was based on a theoretical
dissatisfaction with the persistance of clones demanded by Burnet's
hypothesis and | had not realized that such an important keystone as your
own work had already been fabricated and ready to put into place.

{ would be most welcome to you for the favor of a copy of this article
together with any other papers you would have bearing on this issue. May
| also ask that you send a duplicate copy to my callegue, Or. Gus Nossal,
Hall Institute; Royal Melbourne Hospita}; Parkbille N.2; Victoria, Australia.
I might add that | am expecting Dr. Nossal te join with me for an interval
at Stanford beginning next summer.

1 am looking forward to the possibility of meeting you and discussing
these issues at closer hand at the meetings in Paris next spring.

Yours sincerely,

Joshua Lederberg
Professor of Medical Genetics

Enc: 78A
Ji/mk os

15°

: bo Cc