My experience with laboratory animals leads me to believe that it would be possible for a shrewd animal trainer to direct a dog’s or a horse’s activities by means of eye, facial muscle and bodily movements which are of a too slight excursus to be apparent to ordinary human observation. It is not to be forgotten, in this connection, that some dogs are notoriously dependent on their masters for directive cues, and that this may be characteristic of horses of a certain type. It is conceivable that repetition of a given routine over a period of years might enable a horse to stereotype a highly complex set of habits. On the morning of my appointment with Mr. Sigsbee I found the horse in his stall, unattended. A colored groom, who seems to be the only person, other than Mr. Sigsbee, to have any responsibility for Captain, shortly appeared. He discussed the horse with me without manifesting either suspiciousness or constraint. A little later Mr. Sigsbee came to the stall and asked me to decide how and where to make the tests. He seemed to be wholly unaware of the possibility that my tests might seriously impair the “show” value of his animal. I decided to work with the horse on the stage, and to have Mr. Sigsbee with me. Captain is a nervous, highly excitable animal, and I had previously seen him make a poor showing when not in good condition, hence my desire to have the familiar presence of the master. A careful examination of the stage revealed no evidence of provision for the concealment of a confederate, so I had Captain led upon the stage and began my tests, which were given in the following order: 1. I asked him, “How do you walk when you go to see your girl?” Captain gave an appropriate response, although his master was not within the horse’s field of vision, and did not carry his whip. Mr. Sigsbee who seems to have a great affection for his horse, now interpolated, “What do you give me for sugar?” Captain “kissed” him. 2. At my request Mr. Sigsbee asked Captain to play “Nearer My God to Thee.” I stood between horse and master while the former played the chimes with but one mistake. He received no direction for this after the initial command. Mr. Sigsbee then told me that Captain knew how to run the scale, so I asked for that. The horse made one mistake, due to his failure to strike the trip hammer opposite one of the metal tubes with sufficient force. When he had passed from the low to the high end of the chimes his master commanded him to “come right back,” and this was promptly obeyed. Still no visual cues. As a matter of fact, the horse seemed to pay almost no attention to Mr. Sigsbee with its eyes, as it were, but kept its ears in almost constant movement.