it is related that a mouse had taken up its abode on the brink of a fountain and had fixed its residence at the foot of a tree.
a frog, too, passed his time in the water there, and sometimes came to the margin of the pool to take the air. one day, coming to the edge of the water, he continued uttering his voice in a heart-rending cadence and assumed himself to be a nightingale of a thousand melodies.
at that time the mouse was engaged in chanting in a corner of his cell. directly he heard the uproarious yelling of the frog he was astounded, and came out with the intention of taking a look at the reciter; and while occupied with listening to him, kept smiting his hands together and shaking his head. these gestures, which seemed to display approbation, pleased the frog and he made advances toward acquaintance with him. in short, being mutually pleased with each other, they became inseparable companions, and used to narrate to each other entertaining stories and tales.
one day the mouse said to the frog: "i am oftentimes desirous of disclosing to thee a secret and recounting to thee a grief which i have at heart, and at that moment thou art abiding under the water. however much i shout thou nearest me not, owing to the noise of the water, and in spite of my crying to thee, the sound cannot reach thee, because of the clamour of the other frogs. we must devise some means by which thou mayest know when i come to the brink of the water, and thus mayest be informed of my arrival without my shouting to thee."
the frog said: "thou speakest the truth. i, too, have often pondered uneasily, thinking, should my friend come to the brink of the water, how shall i, at the bottom of this fountain, learn his arrival? and it sometimes happens that i, too, come to the mouth of thy hole, and thou hast gone out from another side, and i have to wait long. i had intended to have touched somewhat on this subject before, but now the arrangement of it rests with thee."
the mouse replied: "i have got hold of the thread of a plan, and it appears to me the best thing to get a long string, and to fasten one end to thy foot, and tie the other tight around my own, in order that when i come to the water's edge and shake the string, thou mayest know what i want; and if thou, too, art so kind as to come to the door of my cell, i may also get information by thy jerking the string." both parties agreed to this, and the knot of friendship was in this manner firmly secured, and they were also kept informed of one another's condition. one day, the mouse came to the water's edge to seek the frog, in order to renew their friendly converse. all of a sudden a crow, like an unforeseen calamity, flew down from the air, and snatching up the mouse, soared aloft, with him. the string which was tied to the leg of the mouse drew forth the frog from the bottom of the water, and, as the other leg was fastened to the frog's leg, he was suspended head downward in the air. the crow flew on, holding the mouse in its beak, and lower still the frog hanging head downward. people witnessing that extraordinary sight were uttering in the road various jokes and sarcasms: "a strange thing this, that contrary to his wont, a crow has made a prey of a frog!" and "never before was a frog the prey of a crow!"
the frog was howling out in reply: "now, too, a frog is not the prey of a crow, but from the bad luck of associating with a mouse, i have been caught in this calamity, and he who associates with a different species deserves a thousand times as much."
and this story carries with it this beneficial advice: that no one ought to associate with one of a different race, in order that, like the frog, he may not be suspended on the string of calamity.