Page:Popular Science Monthly Volume 88.djvu/895

 Popular Science MonthJy

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��What Blood Pressure Means and How It Is Measured

IF for any reason the blood pressure is raised, the blood circulates more freely through the brain as well as through the other parts of the body, giv- ing a feeling of buoyancy and contidence. The man who is working at a terrific rate, howe\er, must have a high blood pressure, but if continued above a safe normal point, it will result in the "burn- ing up" of his vital forces, resulting in many organic as well as nervous dis- orders.

High blood pressure does not always mean one and the same unalterable thing. It may be a sign that the arteries have stifit'ened to such an extent that the heart is taxed to pump the necessary volume of blood through the arteries and with sufficient speed. It may mean an improper condition of the blood it- self — viscosity — the old-fashioned "thick blood" come to life again as a reputable scientific fact. It may mean that the heart has become too big for its job, as when an '"athlete's heart," trained to push a big stream of blood, keeps on trying to do so when the demands of office work do not require it. It may also result from excessive pumping of the heart due to abnormal mental stimu- lation in the form of worry, or continu- ous mental or nervous strain.

A de\ice for measuring blood press- ure, an ingenious instrument called a "manometer," has recently been perfect- ed. The instrument records the pressure of the blood on a diaphragm dial very similar to a steam-gage dial. The scale is di\ided into millimeters.

The apparatus, which is the invention of Dr. Thomas Rogers of Rochester, New York, is one of the most important surgical instruments devised in years, ranking with the pulmotor, stethoscope, and clinical thermometer. Its operation is comparatively simple, but its reading rec|uires an expert. The best results are obtained when a stethoscope is used in connection with it.

The air-bag is first strapped on the subject's arm over the main artery, and is inflated with a bulb attached to it. The operator then adjusts a stethoscope to his ears and finds the pulse. The throb-

���Manometer being used in measuring a man's blood pressure

bing of the pulse against the air-bag is communicated through a rubber tube to the case containing the dia- phragms upon which a \ ihration is set up. These vibrations, which are syn- chronous with those of the pulse, are translated into millimeters by the deli- cate needle of the dial.

��A Clean Way of Removing Pens from Their Holders D K \'I C!•:

��A

���A bent steel wire ejects the pen

��for readily ejecting a pen from its holder without soiling the fingers h a s been in\ented by Joseph H. llrem- er of Tampa, Florida. Mis pen- holder terminates in inner and outer

sleeves, which are slotted longitudinally from their outer ends. In this slot a pen-ejecting bent steel wire slides to push the pen along. The shank of the wire is formed into a ring, which en- circles the penholder. To remove the pen the ring is grasped and forced to- ward the end of the holder, and the bent steel wire pushes off the pen-point and thus spares the fingers.

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