parkinson's: Michael Faraday had mercury poisoning like Pascal and Newton

update:  it appears Faraday had mercury poisoning like Newton, Pascal, and Alfred stock:
http://www.scs.illinois.edu/~mainzv/HIST/bulletin_open_access/num11/num11%20p47-50.pdf



from a biography:

His tragic weakness was recurring “ill health connected with my head,” as he put it. Even as a young man, he had memory problems, and as he grew older he suffered from bouts of depression and headaches. “When dull and dispirited, as sometimes he was to an extreme degree,” his niece Constance Reid recalled, “my aunt used to carry him off to Brighton, or somewhere, for a few days, and they generally came back refreshed and invigorated.” These symptoms increased in severity and frequency until, in 1840, at age forty-nine, Faraday had a major nervous breakdown. Brighton vacations were no longer curative, and for four years he avoided most of his research activities. One can glimpse his desperate condition in a letter to his friend Christian Scho¨nbein, in 1843: “I must begin to write you a letter, though feeling, as I do, in the midst of one of my low nervous attacks, with memory so treacherous, that I cannot remember the beginning of a sentence to the end—hand disobedient to the will, that I cannot form the letters, bent with a certain crampness, so I hardly know whether I shall bring to a close with consistency.”
...

Although he returned to his research in 1845, he was still plagued by periods of memory loss, headaches, giddiness, and depression. He tells about his struggle against increasing mental frailty in letters written to his colleague and close friend Christian Scho¨nbein. In these letters, as nowhere else, Faraday reveals his affliction. Here are some extracts, written between 1845 and 1862, in chronological order: My head has been so giddy that my doctors have absolutely forbidden me the privilege and pleasure of working or thinking for a while, and so I am constrained to go out of town, be a hermit, and take absolute rest. My dear friend, do you remember that I forget, and that I can no more help it than a sieve can help water running out of it. I have been trying to think a little philosophy (magnetical) for a week or two, and it has made my head ache, turned me sleepy in the day-time as well at nights, and, instead of being a pleasure, has for the present nauseated me. Even if I go away for a little general health, I am glad to return home for rest in the company of my dear wife and niece...my time is to be quiet and look on, which I am able to do with great content and satisfaction. In his last letter to Scho¨nbein, in 1862, he said good-bye: “Again and again I tear up my letters, for I write nonsense. I cannot spell or write a line continuously. Whether I shall recover—this confusion—do not know. I will not write any more. My love to you.”