"The blending of the two streams produces a golden fluid, which overflows, flooding a well-tended countryside with fields bordered by rows of trees. Here the knight symbolizes the ego strength that supports the individual in taking charge of the situation, making decisions, and initiating action."
"The stream of urine from the little boy is gray or silver, associated with spirit and with Luna, the changeable. Silver also denotes Mercurius at the beginning of the work. The girl's urine is a golden stream, which refers to soul, sulfur, and Sol. Sulfur and mercury represented opposites qualities of matter, often thought of as masculine and feminine."
"Psychologically, this is the first stage of initiation, which often involves a purification by water, as in baptism. This archetype, so often associated with the education of the young, may be activated in transitional phases at any age; as such, its symbols become a vehicle for individuation. "
"An owl in the lower part of the frame, facing left, is heckled by two birds. This suggest the internal strife and ambivalence attending the wisdom of combining the opposites."
The swans in the Peer represent the transformation of the solitary heron from the previous plate to the start of integration with another as symbolized by the swan, a bird which is very social and mates for life. While the heron stood outside the river, the swans now both swim in the water (symbol of life, but also of a boundary). There may not be enough differentiation in the two birds, and a separation is needed for the process to not stall there and continue into a productive combination of the opposites. The hummingbirds in the Rival, which are very territorial, act as the knight and ego strength necessary for individuation.
Note: the quote is from the book by J.L. Henderson and D.N. Sherwood, Transformation of the Psyche: The Symbolic Alchemy of the Splendor Solis