. Ventilation for dwellings, rural schools and stables. absorb oxygen when in the lungs and ex-change it for carbon dioxide when in the tissues, thus act-ing like so many conveying buckets which are continuouslyloading and unloading with each round trip and yet with-out stopping. Moreover, to make sure that each one of thesecarriers shall be brought in touch with air before it can re-turn to the body, the diameters of the capillaries are madeso small that these absorbing disks are compelled to passthrough them almost in single file with both faces almostcontinuously in touch with the lining me
. Ventilation for dwellings, rural schools and stables. absorb oxygen when in the lungs and ex-change it for carbon dioxide when in the tissues, thus act-ing like so many conveying buckets which are continuouslyloading and unloading with each round trip and yet with-out stopping. Moreover, to make sure that each one of thesecarriers shall be brought in touch with air before it can re-turn to the body, the diameters of the capillaries are madeso small that these absorbing disks are compelled to passthrough them almost in single file with both faces almostcontinuously in touch with the lining membrane of adjacentair cells, thus insuring ample opportunity for the unloadingof the carbon dioxide brought from the tissues, and for thereloading with oxygen to be carried back. There is represented on the right in Fig. 4 a face viewwith a cross-section of one of these oxygen and carbon diox- Carriers of Oxygen-food. 7 ide carriers magnified some 2,650 diameters, and on the lefta single capillary with the corpuscles passing through it insingle M Pig. 4.—Here is seen, on the ripht, the shape of the oxvfrtn and carbondioxide carriers in the blood of man, magnified 2,6% diameters and,on the left, a line of tliem passing single tile through a capillary,magnified about 600 diameters. These carriers of oxygen-food to the body and ofcarbon-dioxide-waste from them, although so extremelyminute, are yet so numerous that the total surface of thecorpuscles in the blood of an ordinary vigorous healthyman measures no less than 49,000 square feet, or more thana full acre. Think of the heart, with its 70-odd strokes perminute, sending more than a full acre of bucket facesthrough the 236 square foot of partition surface in theventilation chamber of the body once every 20 to 40 sec-onds, and the air of this chamber chang«d 15 to 20 timesevery minute! Nor is this the whole storj^ of the structuralarrangements in the mechanism of breathing by which thebody tissues shall be fed
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectventilation, bookyear
