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Es wird das Problem des Chromatins von E. coli an Hand von Robinows Technik untersucht. Der Vergleich zwischen den Färbungsbildern von bestimmten Stufen des Wachstums zeigt, daß regelmäßig geformte Chromatinmassen nur zustande kommen, wenn die Bakterien Vermehrungsvorgänge durchmachen. Dieses Verhalten wird als pseudomitotisch interpretiert, was wahrscheinlich macht, daß die Chromatinmassen mit Chromosomen zu vergleichen sind.

It is shown that the lethal action of nitrogen mustard on spores of Aspergillus niger can be described in terms of the target theory, if one assumes that the intensity of this action varies with time. A two-hit curve can be fitted on the experimental data, on the assumption that a decrease of lethality depends on the inactivation of the substance with time.By diluting the suspension containing the spores with a solution of glycine and sodium bicarbonate, the action of nitrogen mustard is stopped. The lethal action of nitrogen mustard is much weaker at 0° C than at 27° C.Even though exact mutation rates have not been evaluated, an outstanding number of morphological and physiological mutants among the colonies developing from irradiated spores have been observed.

The relation of cancer to ABO groups was studied in 2590 patients with malignant lesions of different sites (except for gastric tumours), in 171 cases of leukemia, and in 117 cases of Hodgkin's disease. 9607 Mood donors were kept as controls.A prevalence of the A group was observed in tumours of the esophagus (148 cases), of the uterus and ovary (188 cases), in myeloid leukemia (71 cases), and in Hodgkin's disease (117 cases). A prevalence of the 0 group was observed in the 37 patients with lymphatic leukemia. However, A and 0 group prevalence was not found to be statistically significant.No relation to ABO groups was demonstrated in tumours of the colon and rectum (489 cases), larynx (121), lung (806), prostata (111), urinary bladder (120), kidney (71), liver and biliary tract (200), and breast (344).The study of larger series of cases is advised for a better evaluation of the relation between cancer and ABO groups.

The association of groups ABO with gastric cancer (1333 cases), gastric ulcer (343 cases) and duodenal ulcer (740 cases) has been studied.No correlation has been observed between gastric cancer and blood groups, whereas an heterogenic distribution of blood groups in relation to tumor site could be noted: e. g., group A was found to be associated to antral cancer, and group O to the cancer of the body and of the fundus.A highly significant heterogeneity of distribution of the groups ABO in the different ages was observed in patients bearing gastric ulcer.The correlation between duodenal ulcer and group O has been confirmed. The relative disease incidence for the subjects belonging to this group was demonstrated to be 55 per cent higher than that of group A subjects.No sex influence on groups ABO distribution was observed in the three studied conditions.

Swiss mice were injected intravenously with 106LD50of MHV-3 virus and, simultaneously, with 2 mg of prednisolone. Control mice were injected with physiological saline and virus, respectively. The animals were killed at different time intervals after the injection and the Spearman-Kärber method was used to determine viral LD50(and relative standard error) in blood, liver, and spleen.Prednisolone produces an increase of viral LD50. This effect occurs after 15-20 hr, with more or less identical intensity in liver, spleen, and blood.Further studies were done by injecting prednisolone intravenously (single dose of 2 mg), not simultaneously with the virus, but 2, 4, 6, 10, 12, and 16 hr afterward and also 12 and 6 hr before.Determination of LD50in liver, at different time intervals after the injection of virus, demonstrated that the effect of prednisolone always occurred 15-20 hr after its administration. This effect was temporary and disappeared in about 10 hr. Furthermore, prednisolone did not appear to influence the eclipse phase of the virus.

THE OH airglow is a sensitive indicator of conditions in the mesosphere. We report the results of measurements of the intensity and excitation temperature in the OH (8,3) vibrational rotational band, carried out with a spectrophotometer of simple design. Light entering a 3 mm diameter iris is collimated with a 170 mm focal length lens and impinges on a narrow band interference filter of 5 cm diameter; the filter has a bandwidth of approximately 3 Å and can be tilted to scan the band between 7300 Å and 7403 Å. The filtered light is detected with a cooled photomultiplier ‘EMI 9558A (S20)’; photon counting is accomplished with a multichannel analyser ‘Laben 100’. An entire scan, including dark current measurements, is carried out automatically in about 20 min. After removal of sky background and dark current the experimental spectra are compared with synthetic spectra obtained by considering the theoretical contribution of all lines of the OH (8,3) band under the assumption of thermal equilibrium. The χ2criterion is utilized to optimize the fitting; best values for the relative intensity and the rotational temperature are obtained at intervals of one hour every night. Observations reported here were carried out for a total of 22 nights and 276 scans during July to December 1969 and for a total of 7 nights and 72 scans during July to December 1968. Data were taken near l'Aquila (42° N, 13° E) at two locations: at Campo Imperatore (2,200 m above sea level) until August 1969 and at Preturo (700 m above sea level) after that date.

WE report here some preliminary measurements of the mechanical properties of a new ceramic material. The material—a pure silica matrix reinforced by carbon fibres—has been made in our laboratory as part of a programme aimed at the manufacture of a ceramic material which, although composed of stiff and brittle components, is itself strong and relatively tough. Such a material forms a good test of current theories for improving the toughness of composite materials, and of reinforced ceramics in particular1.

To the Editor:—We would like to call attention to "Skin Preparation for Lumbar Puncture: Ether or Soap?" (208:1196, 1969). Dr. Harvey Bernard, MD, of the Albany Medical College replied to the question concerning the use of hexachlorophene (Septisol) followed by benzalkonium chloride for skin preparation before lumbar puncture. We would like to submit the following additional information concerning the skin cleansing procedure.Benzalkonium (Zephiran) chloride, along with benzathonium ( Phemerol) chloride, and cetylpyridium ( Ceepryn) chloride are quanternary ammonium cationic surface-acting agents and germicides. When these germicides come in contact with anionic soaps, as are found in hexachlorophene ( Septisol and Phisohex), the large organic ions of opposite charges are attracted to one another, and decrease or destroy the bacteriostatic activity of the cationic surface-acting germicides.1,2When surfaces have been washed with soap they must be thoroughly rinsed with water to remove any residual soap before applying a quanternary ammonium

IN the course of experiments on the bactericidal action of X-rays on the R and S phases of Escherichia coli, it was found that the survival-rate in three stocks (76, 111, Ida), irradiated twenty-four hours after seeding, was different1; one of them (stock Ida) was more resistant to the radiation as compared with the other two stocks. No significant differences were found between S and R phases of the same strains. According to the hit-theory of biological effects of radiation the survival-rate is a measure of the target volume, which has been assumed to represent the bacterial ‘nucleus’2,3. If in the case of bacteria the so-called nucleoplasmic ratio of plants and animals holds true, and if, on the other side, the target volume obtained from X-ray experiments really represents the size of the bacterial ‘nucleus’, one would expect the size of the bacterial cells to be correlated to the target volumes. A biometric analysis of twenty-four hours old bacteria, carried on the projected images of photomicrographs of bacteria stained with Henrici's Congo Red method4, has shown that E. coli with a larger target volume are larger than the ones with smaller target volume. The variability curves obtained for the three stocks were almost normal, and the differences found between their means were statistically significant. It is suggested that such correlation might indicate the presence of polyploidy among different stocks of the same bacterial species, as it has previously been found in other organisms. A detailed description of such experiments will be published elsewhere.