Science from an easy chair / by Sir Ray Lankester.

  • Lankester, E. Ray (Edwin Ray), Sir, 1847-1929.
Date:
1916
Catalogue details

Licence: In copyright

Credit: Science from an easy chair / by Sir Ray Lankester. Source: Wellcome Collection.

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    cells of many varieties—that is to say, all but the micro¬ scopic unicellular kinds—may be considered as composite organisms—cell-states or communities in which the individual cells, all derived from one original mother¬ cell, are the citizens, living in groups and habitations (tissues), having their different occupations and capaci¬ ties, carrying on distinct operations and working together for the common good, the “ life,” as we call it, of the individual plant or animal which they constitute. This comparison should serve merely as an illustration of the individual character and co-ordinated activity of the cells of a many-celled plant or animal. It must not be forgotten that the separate cells are all derived by binary division from the original germ-cell, that they have not come into juxtaposition from distinct sources, but often are held together by threads of their living material, which remain after the process of division of one cell into two. Protoplasm has been called “ the physical basis of life.” Since the activities to which we give the name “ life ” reside in protoplasm, and are chemical and physical activities like those of other bodies, even though more subtle and complicated—we are justified in regarding protoplasm as the substance in us and other organisms which “ lives.” Death consists in the destruction—the chemical undoing or decomposition of protoplasm.1 In simple microscopic unicellular animals and plants, this is obvious—so long as the protoplasm retains its chemical structure it is not “ dead.” Thus, it is possible with many small simple organisms— such as animalcules and the seeds of plants—to dry them, and to expose them to extreme cold, and to deprive them (by aid of a vacuum pump) of all access of free 1 Protoplasm is not a single chemical compound ; it is the name given to the soft, slimy substance of cells, and contains many chemical compounds—proteids, fats, and others ; some on the way to assume greater chemical complexity ; others in process of destruction. The critical highest chemical body con¬ cealed in protoplasm has no generally recognised name. It is a proteid-like body, consisting chiefly of carbon, oxygen, hydrogen, and nitrogen, with some saline constituents. This is the real ultimate “ living matter,” and I suggested in the Encyclopedia Britannica (article Protozoa) in 1886 that it should be called “ plasmogen.”