Women have a far greater risk than men of developing osteoporosis. They have less bone mass to begin with, and with the menopause they lose the hormone oestrogen, which slows bone loss. While postmenopausal women are most at risk, some younger women – marathon runners, gymnasts, dancers and anorexics, for example – can also suffer from osteoporosis.

For many years the cause of cholera was unknown. Theories accounting for the disease ranged from pollution by foul air to one’s elevation above sea level. Even hair color was suggested as a possible culprit…But perhaps one of the most bizarre notions was set fort in a book published in Dublin in 1849. The work of Sir James Murray, a physician, it bore the extraordinary title Electricity as a Cause of Cholera, or Other Epidemics.

Another example of the precision of lasers is in the removal of otherwise inoperable tumors of the brain and spinal cord, where surrounding tissue must be left undisturbed. With conventional surgery it is usually impossible to remove all the malignant cells, which often spread to other parts of the body. Although such operations are still in the experimental stage, it is hoped that before long even the most inaccessible tumor will be within reach of a laser’s cutting beam.