The romance of the human body / by Ronald Campbell Macfie.

  • Macfie, Ronald Campbell, 1867-1931
Date:
1919
Catalogue details

Licence: In copyright

Credit: The romance of the human body / by Ronald Campbell Macfie. Source: Wellcome Collection.

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    atoms clustered together into groups known as molecules. Compared with the chemical combina- tions that we find in non-living substances, cells are amazingly complex. A molecule of water consists of two atoms of hydrogen joined to one of oxygen; a molecule of sulphuric acid consists of two atoms of hydrogen, one of sulphur, and four of oxygen; whereas a single molecule of ‘protoplasm,’ as the living matter is called, con- tains some thousands of atoms. The number of atoms and molecules in a tiny cell is surprising. The liver is made up of thousands of microscopic cells, yet each cell contains about 300,000,000,000,000 atoms grouped together in 64,000,000,000 molecules; while the human ovum, which is smaller than the dot on an i, has been calculated to contain 8,640,000,000,000,000,000 atoms combined together into 1,728,000,000,000,000 molecules. If the protoplasm is to live it requires also to be saturated with water resembling dilute sea water. Indeed, most protoplasm is found to contain about 80 per cent, of water. So much for the chemistry of the cell Let us look now at its shape and microscopical character- istics. A cell may be round, or branched, or elongated. The cells of the liver are round, the cells of the brain are branched, the white cells that float in the blood are branched, the muscle cells are elongated. Seeing how minute most cells are, one would be inclined to think that they cannot have any structure; but they have a very distinct structure, and distinguishable parts. Round each cell is a