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.
Symptoms that mimic hot flashes can occur in both men and women who have a tumor of the hypothalamus or pituitary gland, certain serious infections such as tuberculosis or HIV, alcoholism or thyroid disorders.