We meditate on the river whose water consists of the five streams, which is wild and winding with its five springs, whose waves are the five vital breaths, whose fountain head is the mind, the course of the five kinds of perceptions. It has five whirlpools, its rapids are the five pains; it has fifty kinds of suffering, and five branches.

In plain words: Life is pictured as a wild, winding river. Its streams and springs are the five senses, its waves are the five breaths of life, and its source is the mind. Its rapids and whirlpools are the many kinds of pain and suffering people go through.