jmc

The radius of the circular path of the horse closer to the center is $\frac{1}{4}$ of the radius of the path of the horse farther from the center. Since circumference is directly proportional to radius, the length of shorter path is $\frac{1}{4}$ of the length of the longer path. Therefore, 4 times as many revolutions must be made to go the same distance, which is $27\times 4=\boxed{108}$ revolutions.