The accurate investigation of water and mineral balance in young infants is frequently hindered by losses or admixture of samples during the collection of urine and stools. Apparatus designed to decrease these difficulties should automatically separate the stools and urine, announce the act of voiding by an audible signal and make possible the reading of the volume of each specimen of urine before addition to the total sample.
The outfit used at the New York Nursery and Child's Hospital consists of parts devised to fulfil these requirements. The mattress is a modification of the many types that have already been used,1 and was suggested to us by Gamble.2 The specifications are given in the photograph and legend (fig. 1 A). A local mattress manufacturer can copy or modify these dimensions to meet individual requirements.
The metabolism mattress is placed in the bed on top of the regular mattress