The science of life : fully illustrated in tone and line and including many diagrams

THE COMPLEX BODY-MACHINE AND HOW

blood-stream, coursing and filtering through the muscles, keeps them active and healthy : it brings them fuel to burn and oxygen to burn it with, and it brings matter with which they can repair themselves from the slight wearing away that their working entails ; moreover, it washes away the exhaust gases, so to speak—the by-products of their activity. The bloodstream, be it noted, is not a peculiarity of the muscles ; 1t perfuses every corner, every shred - sulW of tissue in the Nee body, bringing

Fig. 7. A dissection of the san ee forearm, in which some of matters away. the muscles and related parts Ties Gireula are displayed. tion of the blood 4 Hi consists nee of eS 3 centres in the bran g 0 TE AYLETIES ¢ ( ee Ea Gabe), eet (left heart and that is out of the drawing for clearness), in the chest, and nerves (seen as white cords). where also the lungs are accommodated. Need we do more than name the ribs and the midriff enclosing this cavity ? The professor insists on calling the midriff “the diaphragm, a domed muscular partition between the thorax (his name for chest) and the abdomen.” But he points out that the chest is really a conical rib-cage, narrow above and broad below, and that is worth remarking. What we thrust out as our chests when we want to swagger like an athlete is mainly the big muscles on the outside of the thorax which go from the ribs to the arms. The abdomen is singularly unprotected in front, with nothing but a soft muscular wall. Most of us have wondered at times why Nature never foresaw the kick and the stab at our lower vital centres. The liver and stomach indeed cower up under protection

IT WORKS

of the lower ribs, being able to do so because of the domed frame of the midriff, but the poor bowels are dreadfully exposed in a beast that walks erect. The rest of the contents of the abdomen need but the slash of a sharp knife to be spilled abroad, as happens in hara-kiri, that form of suicide so popular in Japan. The abdomen is largely filled with the massive apparatus that digests, absorbs, and handles food—the stomach, the coiling bowels, and so on. Many of these parts are in incessant movement, churning the food inside them, mixing it with the digestive juices, and driving it along their canal by means of forceful rhythmical contractions. At the back of the abdomen, in the small of the back, lie the kidneys, and below is their associate, the bladder; they are the apparatus which weeds out from the blood the poisonous byproducts of the activities of our bodies and ultimately expels them. Moreover, the abdomen contains most of the organs of reproduction.

Large Intestine

Fig. 8. A diagram showing where some of our

internal organs are placed with reference to the

ribs, the breastbone, and other easily recognized surface landmarks.