His chronicle of his trip, The naturalist on the River Amazons, became a bestseller when it was published in 1863.
Hot flashes and nausea are most commonly caused by hormonal imbalances in the body, most notably, by sex hormones. For women, a decrease in estrogen is often to blame, whereas in men, testosterone deficiency can create the problem. Sometimes, the symptoms occur for reasons not related to those hormones at all.
Hot flashes generally are caused by complex hormonal changes due to menopause in women. Hot flashes are described as feeling like a warmth moving throughout the body that begins with the head along with profuse sweating. Men and children also suffer from hot flashes caused by medications, cancer, infections, and other health problems.