كتاب الطهارة
2  
The Book of Purification
(31)
Chapter: The ruling on the urine of a nursing infant and how to wash it
(31)
باب حُكْمِ بَوْلِ الطِّفْلِ الرَّضِيعِ وَكَيْفِيَّةِ غَسْلِهِ ‏‏
Sahih Muslim 287b

This hadith has also been narrated from al-Zuhri with the same chain of narrators. (but for the words):

" He (the Holy Prophet) sent for water and sprinkled it over."
وَحَدَّثَنَاهُ يَحْيَى بْنُ يَحْيَى، وَأَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ وَعَمْرٌو النَّاقِدُ وَزُهَيْرُ بْنُ حَرْبٍ جَمِيعًا عَنِ ابْنِ عُيَيْنَةَ، عَنِ الزُّهْرِيِّ، بِهَذَا الإِسْنَادِ وَقَالَ فَدَعَا بِمَاءٍ فَرَشَّهُ ‏.‏
Reference : Sahih Muslim 287b
In-book reference : Book 2, Hadith 132
USC-MSA web (English) reference : Book 2, Hadith 564
  (deprecated numbering scheme)