The Jataka, Volume I, tr. by Robert Chalmers, , at sacred-texts.com
"In light or dark."--This story was told by the Master while at Jetavana about two Brethren who had joined the Brotherhood in their old age. Tradition says  that they were living in a forest-dwelling in the Kosala country, and that one was named the Elder Dark and the other the Elder Light. Now one day Light said to Dark, "Sir, at what time does what is called cold appear?" "It appears in the dark half of the month." And one day Dark said to Light, "Sir, at what time does what is called cold appear?" "It appears in the light half of the month."
As the pair of them together could not solve the question, they went to the Master and with due salutation asked, saying, "Sir, at what time does what is called cold appear?"
After the Master had heard what they had to say, he said, "Brethren, in bygone days also, I answered for you this same question; but your previous existences have become confused in your minds 1." And so saying, he told this story of the past.
Once on a time at the foot of a certain mountain there were living together in one and the same cave two friends, a lion and a tiger. The Bodhisatta too was living at the foot of the same hill, as a hermit.
Now one day a dispute arose between the two friends about the cold. The tiger said it was cold in the dark half of the month, whilst the lion maintained that it was cold in the light half. As the two of them together could not settle the question, they put it to the Bodhisatta. He repeated this stanza
Thus did the Bodhisatta make peace between those friends.
 When the Master had ended his lesson in support of what he had said as to his having answered the same question in bygone days, he preached the Four Truths, at the close whereof both of the Elders won the Fruit of the First Path. The Master shewed the connexion and identified the Birth, by saying, "Dark was the tiger of those days, Light the lion, and I myself the ascetic who answered the question."
50:1 The compound bhavasaṁkhepagatattā occurs here and in the next Jātaka, and also Vol. i. p. 463 and Vol. ii. p. 137. The meaning of the word appears to be that by re-birth events in previous existences have become jumbled up together so that no distinct memory remains. A Buddha has the power of remembering the whole of his past existences.