It was undoubtedly a bold step to challenge thus openly the man who was acknowledged as the autocrat of science in Britain. Moreover, though he had long felt that on his own subjects he was Owen's master, to begin a controversy was contrary to his deliberate practice. But now he had the choice of submitting to arbitrary dictation or securing himself from further aggressions by dealing a blow which would weaken the authority of the aggressor. For the growing antagonism between him and Owen had come to a head early in the preceding year, when the latter, taking advantage of the permission to use the lecture-theatre at Jermyn Street for the delivery of a paleontological course, unwarrantably assumed the title of Professor of Paleontology at the School of Mines, to the obvious detriment of Huxley's position there. His explanations not satisfying the council of the School of Mines, Huxley broke off all personal intercourse with him. CHAPTER 1.11. 1857-1858. Throughout this period his health was greatly tried by the strain of his work and life in town. Headache! headache! is his repeated note in the early part of 1857, and in 1858 we find such entries as:--] "February 11.--Used up. Hypochondrical and bedevilled." "Ditto 12." "13.--Not good for much." "21.--Toothache, incapable all day." [And again:--] "March 30. Voiceless." "31.--Missed lecture." [And] "April 1.--Unable to go out." [He would come in thoroughly used up after lecturing twice on the same day, as frequently happened, and lie wearily on one sofa; while his wife, whose health was wretched, matched him on the other. Yet he would go down to a lecture feeling utterly unable to deliver it, and, once started, would carry it through successfully--at what cost of nervous energy was known only to those two at home. But there was another branch of work, that for the Geological Survey, which occasionally took him out of London, and the open-air occupation and tramping from place to place did him no little good. Thus, through the greater part of September and October 1856 he ranged the coasts of the Bristol Channel from Weston to Clovelly, and from Tenby to Swansea, preparing a "Report on the Recent Changes of Level in the Bristol Channel."] "You can't think," [he writes from Braunton on October 3,] "how well I am, so long as I walk eight or ten miles a day and don't work too much, but I find fifteen or sixteen miles my limit for comfort." [For many years after this his favourite mode of recruiting from the results of a spell of overwork was to take a short walking tour with a friend. In April 1857 he is off for a week to Cromer; in 1860 he goes with Busk and Hooker for Christmas week to Snowdon; another time he is manoeuvred off by his wife and friends to Switzerland with Tyndall.