Abstract
LONDON. Royal Society, May 2.—Sir Archibald Geikie, K.C.B., president, in the chair.—Dr. Marie C. Slopes: Petrifactions of the earliest European angio-sperms. The paper gives an account of the anatomy and the geological bearing of three new petrified angiospermic stems. These three fossils are all in the British Museum collections. Their age appears undoubtedly to be Lower Greensand (Aptian), and they are consequently the earliest angiosperms of which the internal anatomy is known. They are also of interest as coming from northern Europe at a time when angiosperms have hitherto been supposed not to have penetrated to that region. The three specimens differ so considerably in their structure that it seems justifiable to place them in three distinct, new genera.—Dr. F. Keeble and Dr. E. F. Armstrong: The distribution of oxydases in the plant and their role in the formation of pigment. The methods of investigation in general use do not admit of the determination in detail of the distribution of oxydases in the tissues of plants and animals. Hence the hypothesis that pigments are produced by the action of oxydases in colourless chromogens, though rendered probable by recent researches, cannot be regarded as established. Methods are now described which allow of the macroscopic and microscopic recognition of plant oxydases. By the application of these methods it is shown that in the Chinese primrose (Primula sinensis) the distribution of oxydases in the tissues coincides with that of the pigments of the flower and other parts of the plant. Thus, the hypothesis with respect to the ro^le of oxydases in pigment-formation receives confirmation. It is proved that P. sinensis contains two peroxydases which differ from one another in their chemical reactions and in their localisation. It is proved definitely that dominant white flowers contain a substance which inhibits, but does not destroy, peroxydase. Experiments with recessive white flowers, the genetical behaviour of which indicates that they lack either peroxydase or chromogen, show that they contain peroxydase. Inasmuch as recessive whites contain no inhibitor of oxydase, failure to form pigment is to be attributed to lack of chromogen. The distribution of peroxydases in P. sinensis is to be regarded as typical of that in flowering plants generally, and the method appears to be capable of wide application in the study of the distribution of oxydases.-Dr. B. R. G. Russell: The manifestation of active resistance to the growth of implanted cancer, (i) The reaction which is evoked by the implantation of transplantable tumours of the rodent varies widely with different tumour-strains. The reaction has been determined by exercising all the growths in a series of animals on a given day, and then testing the suitability of the animals for the growth of a tumour-strain growing in 90 to 100 per cent, of normal animals. Some strains do not affect the natural suitability of the animals, others render every animal resistant to re-inoculation, and the remaining strains occupy intermediate positions. (2) The individuality of the animal inoculated may contribute to the development of the resistance, although not to so marked a degree as the tumour parenchyma. (3) Simultaneous inoculation qf a tumour-strain which induces no resistance, and a strain which induces resistance, may be followed by marked inhibition of the growth of the former strain. (4) Mice bearing progressively growing tumours can be rendered resistant to re-inoculation, but the tumour first inoculated need not necessarily be affected. (5) Repeated inoculation of tissues, such as mouse embryo-skin, which renders animals resistant to subsequent inoculation, has not been shown to have a constant effect upon the growth of established tumours. (6) The conclusions drawn in (4) and (5) support the view previously expressed that immunity to cancer is directed mainly against the stroma-eliciting properties of the cancer cells.-Dr. Wm. H. Woglom: The nature of the immune reaction to transplanted cancer in the rat. The paper discusses the reactions to tumour grafts displayed by normal rats and by those rendered resistant through preliminary treatment with tumour or embryo skin. The elaboration of a stroma and the provision of blood-vessels observed in normal rats is absent in refractory animals, irrespective of the method of immunisation.—T. Graham Brown and Prof. C. S. Sherrington: The instability of a cortical point. The reflex reactions obtainable from simple spinal preparations, even when elicited from one and the same receptive “locus,” are subject to a certain amount of variability. The variability is somewhat greater when preparations which are decerebrate are employed. With loci in the motor region of the cerebral cortex the variability is greater still. The experiments reported in this paper were undertaken to examine the nature and extent of the variability of response observable in the reactions from one and the same locus in the motor cerebral cortex. It is found that the inconstancy of response amounts under certain conditions to an actual reversal of the effect of the cortical point as examined in the muscles of the-limb. The factors determining this reversal of cortical effect are examined, and the reversal itself is studied by graphic registration. A prominent factor in the conditions underlying the reversibility of the cortical effect appears to be the quiescence or activity of points of cortex antagonistic in their effect to the particular point under examination.—Dr. J. W. W. Stephens and Dr. H. B. Fantham: The measurement of Trypanosoma rhodesiense. The paper contains the results of the measurements of 1000 Trypanosoma rhodesiense, 400 of which were measured from different hosts, namely, man, monkey, horse, dog, rabbit, guinea-pig, mouse, while the remaining 600 trypano-somes were measured from rats only. The authors' chief conclusions are:—(1) That in the case of dimorphic trypanosomes, like T. rhodesiense, samples of twenty trypanosomes from a particular slide on a particular day are too small, because the average length may vary by as much as 4.7μ. (2) The day of infection on which the sample is taken is very important, as on one day 10 per cent, of stumpy forms may be found and on another day 95 per cent. The authors therefore recommend taking samples of trypanosomes from each day of infection of the host. (3) As the host from which the sample of trypanosomes is taken is probably also important, the authors suggest using the same animal throughout, e.g. a tame rat.
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Societies and Academies . Nature 89, 258–261 (1912). https://doi.org/10.1038/089258a0
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DOI: https://doi.org/10.1038/089258a0