Abstract
THE cellular doctrine lies at the basis of modern bio-o logical research. Living matter in its simple and complex conditions consists essentially of protoplasm with a contained body or nucleus. The two elements plasma and nucleus constitute the elementary organism—the cell. The lowest individual forms1 of life are represented by a single cell, and such unicellular organisms may be either of a Vegetable or animal type. The cells in each instance exist as free living and independent organisms. The higher forms of life are built up of parts in which the structural unit remains the cell, despite the modifications the cell necessarily undergoes as a fixed element in the various tissues and organs. All phases of animal and plant life are demonstrably of cellular origin and organisation, and their vital manifestations represent the summed up activities of cells. Every vital problem, therefore,.-is. ultimately a cellular problem, and a direct study of the cell, in so far as may. be possible,. is the. keynote of biological research. The methods to be adopted will depend upon the problem it is desired to investigate. A histoiogical technique, aided by the microscope, will naturally ibe employed where it is desired to.study the relations of;parts and the structural organisation of the,tissues and their cellular elements. The soluble products o.fc hfs iliving cell spontaneously present themselves for examination by chemical and other means. It is otherwise with regard to the agencies acting and the processes occurring within the confines of the cell. These are naturally beyond the range of the ordinary methods of observation. The essential processes of life are intracellular and intimately bound up with the living substance of the cell, and. of ithese but few data are possessed.,The. importance of the problems involved is as great as their investigation is difficult. The cell exercises its vital functions in virtue of a specific physical and chemical organisation of its molecular constituents.. The ordinary,methods of biological and,cherriical research modify or destroy this, organisation, and;,do not admit, of an intimate. study -of the normal,cell constituents. For this purpose it is essential to eliminate, or. to reduce to, a minimum the influence of external modifying agents on the cell.or its, immediate products. An intracellular physiology can only be based on a direct. study of intracellular constituents apart from their secretions and products. This, in ordinary circumstances, is impossible with respect to actively functionating and intact' cells', It is obvious, therefore, that the first desideratum is a suitable method-of obtaining the cell plasma for experimental purposes, and it is only recently that- this has been successfully aecomplished. The most feasible means of procedure appeared to be the,use oi mechanical agents which, whilst bringing the cell substance within the field of observation- would, -at the same time, be- least likely to affect its eharacter and constitution;- The method consists in a mechanical rupture of the cells and the release of their contents under. conditions favouring the conservation of their properties. The first successful application of this description of method was made by Buchner in the par-tieular instance of the yeast cell, and with brilliant results. ¦f,he researches of Buchner were of wide biological significance, and were suggestive of much, more than a cell-free ajcoholic fermentation of sugars. They demonstrated the ppssibiiities of the new methods with regard to. more general vftal problems. The Buchner process consisted, in a mechanical trituration of the yeast cell with the aid of sand and a subsequent filtration of the resultant mass under, pressure through Kieselguhr. The filtrate contained the expressed constituents of the yeast cell which were capable of passing through Kieselguhr, and the product, in virtue of its fermentative properties, was termed “zymase.”.
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The Application of Low Temperatures to the Study of Biological Problems 1 . Nature 68, 608–609 (1903). https://doi.org/10.1038/068608a0
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DOI: https://doi.org/10.1038/068608a0