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344. From Jacques Loeb
The Rockefeller Institute for Medical Research, New York
Street and Avenue A
Marine Laboratory, Woods Hole, Mass. September 4, 1922
My dear Professor Einstein:
It was extremely kind of you to take the trouble of reading my book and to write
to me in such an appreciative
The reason why the protein molecule only acts
as acid or as base is difficult to explain, except that it is a fact as far as gelatin and
proteins in general are concerned. I have ventured to explain it in analogy with the
experiences on indicators which have shown that the chromophore group of indi-
cators undergoes a tautomeric change at a definite hydrogen ion concentration. As
a preliminary suggestion, I offered the idea that an isomeric change may also occur
in the protein molecule at a critical hydrogen ion concentration.
We were all very much worried and shocked at the turn of events in Germany. I
think it is an excellent idea for you to follow the invitation which takes you across
the seas, and I only wish that you would accept my suggestion that I made to you
a year ago, that you spend several years in the United States. If you would consider
this possibility, I think arrangements could be made whereby you could have full
independence and facilities to work. I do not think that matters will be very much
different in Germany in the next few years. Will you let me know how you feel
about this matter?
I have had to abandon my trip to Germany for the reason that Mrs. Loeb was not
very well and that it looked for a time as if she had to undergo a serious operation.
I could not make up my mind to go to Germany with the burden of that worry re-
sting on my shoulders, and it seemed only fair to me that I should inform the com-
mittee of this situation. It would have been a great satisfaction to me if I had had a
chance to bring some of my results before the physical chemists, since I have a very
limited audience in this country and since in Germany they are not familiar with
the literature published during the
In addition, the opposition on the part of
the majority of the biologists to any application of physical chemistry to biological
problems, and the opposition of the old-fashioned type of colloid chemists like
Wolfgang Ostwald, prevent the dissemination of these facts in German literature.
I hope it will be possible, finally, to get support in this country for those German
scientists who are able to do the right kind of work; if not, I am afraid there will be
added to the brutality following this war the cessation of scientific activity which
can only result in keeping the forces of brutality longer in power.
I remain with kindest regards from all of us to yourself and Mrs. Einstein, Yours