A HISTORY OF SCIENCE 



of coffee and rolls. I do not take a second breakfast 

 at ten or eleven, as many Germans do, but work con- 

 tinuously until one o'clock, when I have dinner. This, 

 with me, as with all Germans, is the hearty meal of the 

 day. After dinner I perhaps take a half-hour's nap; 

 then read the newspaper, or chat with my family for 

 an hour, and perhaps go for a long walk. At about 

 four, like all Germans, I take my cup of coffee, but 

 without cake or other food. Then, at four, having 

 had three full hours of brain-rest and diversion, I am 

 ready to go to work again, and can accomplish four 

 hours more of work without undue fatigue. At eight 

 I have my rather light supper, and after that I at- 

 tempt no further work, giving the evening to read- 

 ing, conversation, or other recreation. I do not retire 

 till rather late, as I require only five or six hours' 

 sleep." 



Such is the method of labor division that enables not 

 Professor Haeckel only, but a host of other German 

 brain-workers to accomplish enormous labors, yet to 

 thrive on the accomplishment and to carry the rug- 

 gedness and health of youth far into the decades that 

 are too often with our own workers given over to de- 

 crepitude. Haeckel at sixty-five looks as if he were 

 good for at least a score of years of further effort. 

 And should he fulfil the promise of his present rugged- 

 ness, he will do no more than numbers of his col- 

 leagues in German universities have done and are 

 doing. When one runs over the list of octogenarians, 

 and considers at the same time the amount of the in- 

 dividual output of the best German workers, he is led 

 to feel that Professor Haeckel was probably right in 



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