SCIENCE SIFTINGS

New Zealand Tablet, Volume XLIX, Issue 20, 18 May 1922, Page 46

SCIENCE SIFTINGS

. ===== By “VOLT” [= -■==

OUR DEBT TO THE SUN. Apropos of its announcement that the Medical Research Council has appointed a committee to investigate the effects of light on the human body the London Times says that research has suggested that in our environment lie many factors which greatly, even profoundly, influence our reactions to disease. Many of these factorsnow called the third partners in diseaseare of a mysterious kind, and .are but little understood. Some of them favor the onset of disease, others make the soil very unfavorable for the seed. Chief among the latter is the sun, that greatest physician. Last summer, when London streets were drenched with pure, unfiltered sunlight, and it was possible to acquire a “tan” in Piccadilly, the health of the city and of the country in general improved very greatly. Nowhere as the improvement more marked than at that “Sunlight Sanatorium,” the Lord Mayor Treloar’s Homo for Crippled Children at Alton. The pioneer work which Sir Henry Gauvin is doing for surgical tuberculosis at the home has been already referred to in The Times. His method is to avoid operation and trust to sunlight, fresh air, and good food. Last summer the sun justified the best hopes entertained of it. ! THE BRAIN IN ACTION. In the strictly limited sense in which we are righthanded we are left-brained. As I write these words with my right hand (states a doctor in a London paper) it is the left side of the brain that starts and controls the movements of that hand. But that thought and memory involved are initiated from neither the right nor the left side of the brain; those “higher centres” are not definitely localised. However, the “centres” for all the movements of the body are. Place your hand flat over either ear in such a way that the tips of the fingers reach the summit of the scalp and it will cover, on either side, the area that governs the movements of the opposite half of the body. Direct experiment on animals and the results of disease in human beings have enabled doctors to construct a complete map of this motor area of the brain. When a man has a “stroke” and loses the use of his right arm and his right leg and the right side of the face, we know exactly where the damage is on the left side of the brain. And the outlook is less unfavorable if the left half of the body is paralysed, because speech is governed by a centre in the left side of the brain. Most people are right handed. They learn to use their right hand for writing and other purposes from childhood, and its muscles are more J quickly responsive to the brain. But the left hand has an equal capacity of development. As well as being right-handed, we are also right-legged. If you were placed in a' field blind-folded and directed to walk in a line straight ahead you would find that you would eventually return to somewhere about the place you started from, after describing a wide circle towards the left. This has actually occurred to many who have set out to cross a wide common in a fog, and it is due to the fact that the right leg habitually takes a very slightly more powerful step than the left. That is also the reason why the shoemaker tries a shoe on your right foot for preference. As the muscles of the right arm and leg are more constantly employee! and more quickly respond to orders which we know came from the left side of the brain, it is fair to assume that the “centres” there that control them are more highly developed, and in that , limited sense we are left-handed. But in no other. Sight and hearing are governed from both sides; thought, memory, sensation, and feeling are no more placed on one side than on the other.. We live and move and exist in the brain alone. The rest of the body ,is but an instruemnt to carry out its orders. • , ■