Far more important, however, in Darwin’s career, as a drawback to scientific observation, than any intrusions of subjective sympathy, were the bitter, persistent limitations of physical illness and weakness. During a very large part of his life he was tormented by nervous indigestion, manifesting itself, under any strain, in persistent nausea. This first appeared in the ever-returning and unconquerable sea-sickness which made all his southern voyages a misery. When the ocean was at all boisterous the malady prostrated him, and those who know how absolutely prostrating sea-sickness is will appreciate the positive heroism which enabled him to prosecute his journey and his researches with such a handicap. After his return to England the trouble continued to hound and haunt him through all his later years. He never could work for more than a small portion of the day. The excitement of visitors always upset him. There were long periods when any work was impossible and often an absorbing investigation had to be laid aside altogether just at the most critical point, laid aside so completely that not only actual labor but even thought was prohibited. The idleness which he detested was forced upon him for a very large part of his days and hours and the spirit framed for such constant and intense activity was obliged to discipline itself to the most irksome and profitless repose. It made no difference in the intensity or the persistence of his scientific preoccupations. Perhaps if he had abandoned his pursuits altogether and had contented himself with an indolent and externally diversified existence, he might have enjoyed reasonable health. But he would not yield for a moment. His whole soul was in the studies, the pursuits, the investigations that enthralled and inspired him, and life without them would have been inconceivable. ‘We have come here for rest for me, which I have much needed; and shall remain here for about ten days more, and then home to work, which is my sole pleasure in life.’[54] That is the constant note. In the midst of his travels he wrote home: ‘My mind has been since leaving England, in a perfect _hurricane_ of delight and astonishment, and to this hour scarcely a minute has passed in idleness.’[55] The body might lag and drag and harass and torment, but the spirit lived in just such a hurricane of excitement and enthusiasm always. IV