WARNINGS FROM DARWIN AND AGASSIZ 



on the brow if he does not incline at once to sleep, and 

 a foot-bath with hot or cold water, as the state of the 

 system requires, is a common resource, and it seldom fails 

 to quiet him. 



" After a year or two he was conscious of discomfort 

 in the cerebellum when he had done too much, and to 

 this day that note of warning can never be disregarded. 

 When he has had most of that trouble, he has found 

 benefit from chopping wood as a form of exercise, it 

 tending to draw off the circulation from the cerebellum. 

 He has never been quite sound since the summer of 1859, 

 and we have long since ceased to expect it, and learned 

 to be thankful if, day by day, he was able to do the 

 essential duty that it brought. Two or three hours a 

 day are his usual limits of work, and there have been 

 many periods when, for months at a time, he could do 

 literally nothing. Now he does nothing in the evening, 

 nothing at all in the way of society even in the most 

 quiet way." 



It is remarkable that two other contemporary natural- 

 ists, who were themselves overcome by work, kept 

 preaching to Dana the sermons that he might have ad- 

 dressed to them. Agassiz broke down in the middle of 

 his career although he recovered his vigor and retained 

 it until a short time before his death. Darwin also was a 

 frequent sufferer during the latter part of his life. The 

 warnings of these two men to their indefatigable brother 

 against " overwork " would be amusing if they were not 

 pathetic. Their letters are given beyond. 



The consideration of Dana's colleagues in the faculty 

 is illustrated by this letter : 



FROM PROFESSOR T. A. THACHER 



" NEW HAVEN, February 23, 1869. 



" Yours of the 2oth came to hand yesterday. I had 

 not heard of or suspected the nature of your illness and 

 I hope that all the threatening symptoms may pass away, 

 as I have known them to do partially or entirely, in one 



'9 289 



