Cambridge University says mathematician and physicist Stephen Hawking remains hospitalized. Gregory Hayman, the university's head of communications, said Tuesday that Hawking “was comfortable and kept in overnight” at Addenbrooke's Hospital. Hawking has been described as feeling “very ill.” Hayman has said the British mathematician and physicist was fighting a chest infection. Hawking, 67, gained renown for his work on black holes and has remained active despite being diagnosed at age 21 with ALS, (amyotrophic lateral sclerosis), an incurable degenerative disorder also known as Lou Gehrig's disease. Hawking has been almost entirely paralyzed for years and communicates through an electronic voice synthesizer activated by his fingers.