Back by popular demand, more insights from the textbook, Introductory Physiology and Hygiene, by H. W. Conn, Ph.D., published by Silver, Burdett and Company, in 1908.
Apparently the Tour de France riders never learned as children that they should sit straight, ride slowly, and stop before they are too tired. However, they did learn about the importance of ‘out-of-door’ exercise.
The handwriting over the chapter title reads “Begin” most likely marking the start of a lesson or assignment. Almost all the chapters have this, and the end of the chapter on ‘How to strengthen the muscles’ has the handwriting, “End of 1st quarter.”