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organic—acids as well. (7) It would be very good for you to lie down from time to
time and make hot wraps for your stomach. Heat always does serve as a regulator
for derailed bodily functions. So it is quite good for you to use them for hours on
end—such as by tying on a hot-water bottle. That won’t bother you in the least
while working. (Perhaps you recall that I consulted you once about the manufacture
of a transportable heat source; you could use such a thing now.)—
I hope that a gastric ulcer is not giving cause for your complaints, that it is mere-
ly a nervous disorder. In any event, it should be a warning to you not to demand too
much of your central nervous system. When a motor is overheated, it must be
turned off so that it can cool down; otherwise it could get permanent damage. Like-
wise, you should put in a break while at work, too. The organs can suffer irrepara-
ble damage not just from exterior harm but also from excessive strain.—
Please do in any case keep me informed, irrespective of the outcome of the ex-
amination and the success of the above-indicated measures of comportment.—
What you report about d’Hérelle’s proofs for the organized nature of his virus is
very
interesting.[3]
Given the resemblance between some properties of colloidally
dispersed material and living material, the gradual adaptation by the virus to a me-
dium of increasing acidity ought to be studied in all directions before one is per-
mitted to decide on this or that one; the word “adaptation” reckons very detrimen-
tally here. ¢There is the familiar “aging” of colloidal solutions which attends the
changes in the state and the reaction. The dilution rate of colloidal solutions largely
governs their dispersiveness.² I know very well that this characteristic is the main
argument for the hypothesis of living carriers of d’H[érelle]’s phenomenon. But it
is precisely the circumstance that other observations speak against this hypothesis
that makes this problem so immensely interesting. Perhaps the virus really is the
link midway between animate and inanimate matter. Only when its absolute size is
known will one have come somewhat further along; then one will see whether it
can be composed of a larger number of protein molecules or whether it is even
smaller than such a thing. Moreover, one would be in a position to produce concen-
trated suspensions of the virus; in short, I believe that calibrated ultrafilters could
prove to be of major use to research. I am very curious about d’H’s verification of
the distillation experiments; the paper does make a good impression.—
I am exceedingly pleased that you will be returning within the foreseeable future
and that you are then going to report to me about your work. I thought you first
wanted to await the outcome of your experiments before you started the theoretical
work. This does involve the experiment that started with the assumption of an in-
crease in the wavelength of monochromatic X-ray light upon
scattering?[4]
Hope-
fully I shall be able to get a vague inkling of the essentials of your work in broad
outline when you present it to me; I always did get such an indescribable pleasure