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.
Pregnancy is one of the root causes of hot flashes in women. Women's hormone levels can fluctuate greatly during a typical lifetime. Hot flashes during pregnancy, perimenopause and menopause are common occurrences. In fact, hot flashes are the most common symptom of menopause.