143, Regent Road,
Salford, 5.

7th May, 1953

Dear Professor Lederberg,

Thank you for your letter of the 30th April which I received
two days ago, The Air service does,in fact,seem to be quite good,
indeed it compares favourably with the internal service in its speed,

I think that the copies which you so kindly sent should be
adequate, With all due respect to the U.S,,and its educational
institutions,I had not till recently required so many, in duplicate
or triplicate, of those various bits of paper which go under the
names of Certificates, Diplomas, etc, Up till now I had always looked
upon them as so much impedimenta which one collected as a by-product
of life, particularly in its academic aspects, I now see how wrong I
was, I will,indeed,make certain that I am fully loaded with all the
necessary documents to prove my civil, military, and academic status,

The visa application moves slowly, I am at present still bringing
together yet more essential papers in order to complete my apclication,
I gather that most of the present difficulties are due to the recent
revision of the Immigration Law and the effect of the McCarran Act,

The question of tha antigenic constitution of the 0111 and055
types of Bact, coli is one which has been recently interesting me,
It seems unusual that one can only find each of these respective 0
antigens in association with one particular K (B), That the O and K
are in fact separate entities must,I think, be accepted on -immunological
grounds, It is unfortunate that the B antigen, at least ints binding
capacity is so indestructible, I have recently tried the ef*ect of
differingstrengths of alkali, following up a suggestion of Dr. Felix
which appeared in a recent Journal of Hygiene. the ‘antigen is resistant
to exposure to N2, Na OH at room temp. for 4 hours, at this level the
organism has become very rough but will @til! strongly absorb B
antibody. It Rie? therefore, be very useful from this point of view,
as well as he ntrinsic interest attaching thereto, if a separation
can be effected genetically, We have had quite a high incidenceof
055 infections here in the last few months ~ in this area they have
been at a higher level than salmonellas,

On re-reading my first paragraphs I feel that I may have given
a wrong impression, I hope that you will understand that it is
merely an expression of some slight vexation I am at present under-
going because of these visadelays. In fact,I have no doubt that it
will ell straighten itself out in the end, It is just rather annoying
at the present, besides the fact that it so fre,juently causes me to

over
bother you yet again,

Once again let me thank you for the kindness and help which
you have shown so far,

Yours sincerely, a

oe
: eer

Aker

.