Popular Science MonthJy 



867 



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. 



