The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqa'iq)
Muslim :: Book 42 : Hadith 7074
This hadith has been narrated on the authority of Isma'il b. Khalid with the same chain of transmitters and the words are:" One amongst us would relieve himself as the goats do without anything mixing with its excrement."