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.
Some premenopausal women who have their ovaries removed can experience severe hot flashes due to surgical menopause. Chemotherapy-induced medical menopause can cause hot flashes, as can hormonal therapies such as tamoxifen. Overall, the severity of hot flashes can vary from mild to moderate to severe.