BIOPHYSICS

I. E. El’piner, L. I. Stekol’nikov. The effect of ultra-sonic waves on alkaloids — 219

BIOCHEMISTRY

N. A. Andreeva, L. S. Kutseva, L. J. Areshkina. On the contribution of folic acid and vitamin B₁₂ to the synthesis of purines by cells of Escherichia coli 113-3 — 223

V. S. Il’in, G. V. Titova. Reproduction of the effect of insulin on the activity of liver hexokinase in vitro — 227

A. E. Kalmanson, L. P. Lipchina, A. G. Chetverikov. Different sensitivity to propylgallate in proliferating and non-proliferating tissues — 230

A. N. Parshin, T. A. Goriukhina, E. A. Sherstnev, L. M. Vdovichenko. The formation of carnozin in the liver and muscles of the frog — 233

ZOOLOGY

V. E. Zaika. The endemic nature of fish parasites in lake Baikal — 236

T. B. Sablina. A contribution to the ecologic-amorphological description of the digestive tract in Cervus tarandus and C. alces — 240

PHYSIOLOGY

I. A. Val’tseva. On variations in the biological activity of the encephalon cortex and respiration under the influence of the venom of Naja tripudians var. cocca Gmel. — 244

I. I. Isaeva, V. K. Krasusskii. On the inheritance of the reaction of the central nervous system of dogs to caffeine administration — 248

EMBRYOLOGY

B. P. Tokin. On the regeneration capacity of Ctenophora — 252

LETTER TO THE EDITOR

As K. M. Fishman kindly pointed out to me, in my article “On the equivalence of certain unbounded operators in a Banach space,” published in DAN, vol. 137, No. 4, 1961, the definition of the operator \(T\) must be made more precise.

This clarification can be made by requiring that, for every \(q = 0, 1, 2, \ldots\) and \(r = 0, 1, \ldots, n - 1\), the inequalities \(0 < \tilde C \le \dfrac{\|M_0^{-q'}\|}{\|L_0^{-q}\|} \le \tilde{\tilde C}\) hold, where \(q' = \left[\dfrac{qn + r}{v}\right]\), and \(\tilde C, \tilde{\tilde C}\) are constants independent of \(q\).

I. V. Gel’man