Verily Dadhyak Atharvana proclaimed this honey (the madhu-vidya) to the two Asvins, and a Rishi, seeing this, said (Rv. I, 116, 12): 'O ye two heroes (Asvins), I make manifest that fearful deed of yours (which you performed) for the sake of gain, like as thunder makes manifest the rain. The honey (madhu-vidya) which Dadhyak Atharvana proclaimed to you through the head of a horse,'...

In plain words: This teaching of honey was first given by the sage Dadhyak Atharvana to the Asvins, twin gods of healing. A Vedic poet praised the bold deed of the Asvins, who received it from him through the head of a horse.