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 may be a side effect of some prescription medications. Raloxifene (Evista), commonly prescribed for osteoporosis, and tamoxifen (Tamoxifen and Nolvadex), a treatment for breast cancer, may cause skin flushing and hot flashes. Hot flashes may be a side effect of chemotherapy too. You may also feel flushed after taking tramadol, a prescription pain reliever. However, this side effect is rare. Some over-the-counter medications can also cause symptoms that mimic those of menopause-related hot flashes.