The Day the Universe Changed - James Burke [105]
While this desire to improve sewerage, water supply, ventilation, procreation, private conditions and the working environment appeared enlightened, it stemmed largely from the mercantile tendency to see welfare as a predominantly economic and political matter. In 1820 Benoiston de Châteauneuf wrote: ‘It is important for the happiness of all that man be placed under the sacred care of the physicians…. Who is better qualified… than the physician who has made a profound study of his physical and moral nature.’Nine years later two simultaneous events were to help to bring this radical approach to public health and state intervention into common use throughout entire populations before the end of the nineteenth century.
The first event was the arrival of a disease that had been travelling towards Europe from northern India at a speed of five miles a day for more than a decade. In 1829 it struck Europe for the first time and Austria, Poland, Germany and Sweden learned the full horror of cholera.
In 1817 a cholera epidemic broke out in the Ganges delta and spread inexorably towards Europe. The growing panic with which it was awaited was due to the unknown nature of the disease and its origin in the mysterious East.
One of Purkinje’s great microscopic discoveries: the neurons in the cerebellar cortex of the brain, known as Purkinje cells. They look like nests of fibres, top right.
The second event was the invention of the achromatic microscope in the same year by a London wine-merchant called Joseph Jackson Lister. From its appearance in the seventeenth century the microscope had suffered from two major problems. Rays of light coming through the outer area of the lens would bend asymmetrically and converge at different focal points, thus producing an image that was out of focus. As the rays were bent, prismatically, the different colours making up white light would also bend to different extents, causing colour fringes to make the fuzzy image even less clear. These effects were known as spherical and chromatic aberration.
Lister’s improvement consisted of a plano-concave lens of flint glass joined with a convex lens of crown glass. The effect was to eliminate the aberrations and provide a clear image. The new achromatic microscope stimulated the obsessive German desire to discover the fundamental processes of life. In 1831 Mathias Schleiden first saw the cell nucleus. These curious holes in tissue had already been seen in plants. In the late seventeenth century Marcello Malpighi had described them as little ‘sacks’. Others had likened them to beer froth. In 1809 G. R. Treviranus had separated out the cells of a buttercup and revealed the partition between the cells to be a double wall. Cells, whatever their function, were separate entities.
Not long after Schleiden had seen the nucleus at the centre of the cell he discussed it with a colleague, Theodor Schwann. Schwann decided to examine every kind of tissue known to him. His microscopic and thorough research was to bring about a major change in the concept of the origin of disease. In his book, published in 1839, Schwann stated that all vegetable and animal tissue was essentially the same. ‘There is one universal principle of development for the elementary parts of organisms, however different,’he wrote, ‘and that principle is the formation of cells.’It is interesting to note that before he published, Schwann submitted the book to his local bishop in case he should be subsequently accused of heresy.
Schwann observed that cells were grouped differently in different tissue. In blood or lymph the cells were independent and isolated. In the epithelium they were independent but in combination. In bone they were welded together by intercellular substance. In tendon and elastic tissue they were fibrous. Each cell had an independent life of its own and came into existence, Schwann theorised, either inside or near another cell, through a process of differentiation of common basic substance.