In a well-marked case there is usually an initial rigor - in children convulsions - followed by a rise of temperature, with vomiting, headache, giddiness, intolerance to light; pain in epigastrium, back and limbs; sleeplessness, apathy or delirium.
In large doses it is a poison causing giddiness, deafness, salivation, sweating and convulsions.
Soon after the publication of Vivian Grey, Disraeli, who is said by Froude to have been "overtaken by a singular disorder," marked by fits of giddiness ("once he fell into a trance, and did not recover for a week"), went with the Austens on a long summer tour in France, Switzerland and Italy.