PROLONGED ILL-HEALTH 

 CONTINUOUS ILL-HEALTH 



Dana's intellectual activity, continued beyond the four- 

 score limit, is the more remarkable when his continued 

 ill-health is borne in mind. 



In the early autumn of 1859 ( as was stated in the ninth 

 chapter), he broke down and went abroad in order to re- 

 cruit his health. Here is his own note of his first breaking 

 down: 



" Editorial duties connected with the Journal of Science, 

 and college duties during the spring and summer of 1859, 

 in addition to the writing of mineralogical and three 

 other articles for the Journal of Science, and some essay- 

 writing for the New Englander, and also the preparation 

 of a Manual of Geology, besides work on the scientific 

 department of Webster s Dictionary, led to a breakdown 

 in July of that year, the difficulty being an overworked 

 and tired head. Unable to work, or even to engage 

 in conversation without unnatural fatigue of head, in 

 October I left for Europe with my wife. I visited 

 France, Italy, and Switzerland, and in August, 1860, re- 

 turned, having gained but little, and that little mainly 

 among the glaciers of the Alps. The rest of 1860, and 

 all of 1861, was spent doing nothing hopeful and cheer- 

 ful, as I had ever been, and seeing some small progress 

 towards health with the passing months." 



He was absent ten months and came back somewhat 

 improved. 



A few years later, in December, 1862, he wrote to Dar- 

 win: " I have worked to great disadvantage, from one to 

 three hours a day, and often not at all. I am now re- 

 suming my duties in the University, but an hour's inter- 

 course with the students in the lecture-room is a day's 

 work for me." Some years afterwards, in 1869, he broke 

 down again, and Professor Marsh read his lectures to 

 the senior class. Then followed a severe fever, from 

 which he slowly recovered. In 1874, he was again 



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