MICROBIOLOGY

T. V. Finogenova. The effect produced by the concentration of Fe in the medium on the synthesis of porphyrins by the Nocardia erythropolis culture . . . . 718

BIOCHEMISTRY

B. F. Vaniushin, N. A. Kokurina, A. N. Belozerskii. The composition of DNA, and certain problems of the evolution of photosynthesising bacteria . . . 722

M. N. Zaprometov, A. K. Karimdjanov. On (+)-catechin from the cotton plant 726

A. A. Krasnovskii, N. N. Drozdova. Reversible photochemical oxidation and reduction of chlorophyll, bacteriochlorophyll and bacterioviridin in a viscous medium; differential absorption spectra of intermediate forms 730

A. I. Medvedev, W. L. Kretovich. The course of biosynthesis of lysin in plants 734

PLANT PHYSIOLOGY

R. K. Saliaev. Electron-microscope examination of the «free space» of root cells, and the role it plays in water absorption . . . . . . . . . . . . . . 737

MORPHOLOGY

A. A. Milokhin. Morphological proof of afferent innervation of vegetative intramural neurons in the oesophage of mammalians . . . . . . . . . . . 739

I. K. Svanidze. Structural alterations in the optical analyser of white rats following enucleation . . . . . . . . . . . . . . . . . . . . . . 743

PARASITOLOGY

A. Strelkov. Intersexes in Tendipedidae, arisen as a result of infection with Mermithidae . . . . . . . . . . . . . . . . . . . . . . . . 745

EMBRYOLOGA

N. N. Fedorova. Development of the uterus, and period of appearance of its congenital anomalies in the course of intrauterine life in man . . . . . . 749

CORRECTION

The definition of a “pure sequent” given in my article (V. A. Matulis, “Two variants of the classical predicate calculus without structural rules of inference”), published in Doklady AN, vol. 147, no. 5, 1962, is not consistent with the subsequent exposition.

The new definition of a pure sequent is as follows.

We shall say that a sequent $S$ is a pure sequent if, first, no object variable occurs in $S$ both free and bound at the same time; second, the sequents $S$ and $\varphi(S)$ are graphically equal; third, in the sequent $S$ there are no two occurrences of quantifier complexes having one and the same proper variable.

V. Matulis

T-13072  Signed for printing 11/IX-1964.  Print run 4990 copies.  Order 982

Paper size 70×108¹/₁₆  Printed sheets 22.4+3 inserts.  Paper sheets 8.0  Publishing sheets 22.8