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Paper chromatography is very helpful in the identification and comparison of antibiotics, but very few results from the application of this technique have been published so far. The awakening of interest in the search for antibiotics which are active against fungi pathogenic to plants and animals makes the investigator aware of the scant information that is available to help characterize such agents. A knowledge of the Rf values of the known antifungal agents would help advance the search for such therapeutic materials. Often these values, in conjunction with the biological inhibitory activities, are the only criteria by which one can determine whether the unknown agent appears to be a new material. When the Rf data are obtained for shake cultures, one can eliminate many previously described antibiotic-producing organisms from further study, thus allowing more research to be applied to antibiotics which are new and different. The studies reported in this paper should serve as a guide to the identification of some of the known antifungal antibiotics.

THE results of an investigation of the application of paper chromatography to the identification of the common barbiturates were recently reported by this laboratory.1 If a barbiturate is found to be responsible for a medicolegal death, the investigator is compelled to engage in as complete and detailed a study as biologic material available allows so that the results can be fully evaluated and the drug identified. Important factors in the final appraisal are the metabolic fate and distribution of the barbiturates in the human body. It is here that the advantages of paper chromatography may be realized, for this simple . . .

An experiment recently described in this Journal (Greenwood, Newbold, Topley and Wilson, 1926) dealt with the after–life of mice that had been previously exposed to epidemic pasteurellosis, and led to the following deductions:“We think we have proved—(1) That the survivors of herd-exposure to epidemic pasteurellosis are more resistant to subsequent exposure than healthy animals not previously exposed to risk.(2) That this superiority is significantly correlated both with length of previous exposure independently of its severity, and with severity of previous exposure apart from its duration.We think it is probable that—(3) The severity of the prior exposure as measured by the average deathrate during the period of exposure, is less important than the length of exposure.(4) The advantage of exposure at first increases with its duration and then decreases, so that mice who have been exposed for a moderate time are more resistant to subsequent exposure than mice who have been exposed for a very short or a very long time.”The results of an independent experiment, similar in kind, with the difference that the after-life and previous exposure took place in a single cage, and covering 1867 mice, support(1), (3) and (4) of the above deductions, also (2) so far as it relates to length of previous exposure, but the severity of previous exposure apart from its duration shows a negative but insignificant association with improved expectation of after-life. These results are in agreement with the suggestion inspired by the experiment previously described. “That these facts are difficult to interpret in terms of pure selection and more easily reconciled with a process of active immunization during the primary exposure, but that the nature of this process will remain obscure until we have more experimental data at our disposal.”

Since the wax, investigations of virus diseases have been in many directions remarkably fruitful, and the experi mental methods employed have been pursued with such intensity in particular instances that the results have illuminated many hitherto obscure problems concerning the interaction of host tissue with parasites, both visible and invisible. Intimate tissue changes have also received their full measure of attention. I emphasize this point because it has been said, with considerable truth, that the advent of the bacteriological era, with the possibility of demonstrating the causative agents of infectious disease in the tissues, has had the effect of withdrawing attention from the minute histological study of the interaction between host and parasite. The early phases of this interaction are still little understood.

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The meaning of the footnote on p. 162 is somewhat ambiguous and the statement comprised in it is not true for all values of n, the number of differences in N.F.T. of which the significance of the mean is tested.The statement that, by the use of a certain approximate distribution, significance of an observation is underestimated means that the estimated value of P in the neighbourhood of the significance level is greater than the true value.

A number of epidemiological and clinical studies have recently shown a considerable increase in incidence of occlusive arterial diseases in smokers, most conspicuously among young individuals. A central role of tobacco smoking in the development of arteriosclerotic cardiovascular disorders has long been suspected, but the basic pathogenetic mechanisms responsible for such an atherogenic effect of tobacco smoke remains to be elucidated. For several years attention was focused on the action of nicotine and other alkaloids on the cardiovascular system; but it is important to stress that it has never been possible through the action of such substances to produce lesions in the vasculature which can be confidently accepted as atherosclerotic in nature.