Relation Between Work and Fatigue.

When research noted this poisoning of the bloodstream, laboratory methods were devised to find out more about the connection between work and fatigue. Mosso perfected a small machine, which demonstrated beyond all doubt that fatigue was one of the greatest handicaps labour had to face. The machine was a simple contrivance, which demanded what was known technically as “work” by an isolated group of muscles. The machine, called an Ergograph, has since been modified and improved, but as the principle involved is the same in all machines, we may, with profit, describe it. (See Fig. 1.)

The arm is clamped in so that free arm movement is impossible; the first and third fingers are inserted in cases, which hold them firmly and so prevent movement there. The middle finger is left quite free to move in any way. When the experiment starts, the finger is inserted in a sheath attached to a wire, which runs over pulleys, to be attached to the weight. Every time the finger is raised (i.e., doing work) the weight is lifted. The contractions are continued until the finger is fatigued. By changing the weights, different conditions can be attained, and the amount of page 29 work can be calculated from the given data.