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.
Although hot flashes are a characteristic symptom of perimenopause, rare tumors, and other medical conditions may sometimes also cause hot flashes. Taking certain medications, eating spicy foods, and the consumption of alcohol have also been associated with the occurrence of hot flashes.