The opponent asks, “How do you know this is the normal slope, and that the patterns you describe are not normal, and what you describe as normal is not a variation?” This is a perfectly proper and timely question and can only be answered fully by examination of and noting a large number of draught horses. The Normal Arrangement on the Ventral Surface of the Horse’s Neck. This examination has been made in a number of specimens large enough to satisfy the most exacting opponent. In all, 748 were examined as to the hair on the under surface of the neck and 338 of these presented the normal arrangement and 411 showed patterns of various kinds ranging from a trifling reversed area two to three inches long on one side of the middle line, to a finely-formed whorl, feathering and crest occupying the whole of the surface where the collar is able to reach. These two limits are shown side by side in the figures. I should add that among the 411 which I term abnormal, for the sake of clear contrast, the number of varieties of pattern were numerous and bewildering. Cart Horses. A very significant result followed from a special examination of 300 cart horses, as distinguished from hackneys. These showed the astonishing number of 277 specimens of what I call the abnormal and only 23 of the normal type. This special group in no way weakens the force of the larger study of 748, for the 300 cart horses are included in it, and, if removed, would have left the normal specimens in the hackney or general group very much more numerous. Looking at the cart horses, which are specimens of a highly-specialised breed for heavy draught purposes, one may assert with some confidence that, _for them_, the normal pattern of the hackney is becoming their abnormal. It must be remembered that these great creatures with large muscular necks are during most of their time of work pulling hard against the collar, and the very conditions required for making patterns of hair through pressure of harness are present in a remarkable degree. It is indeed an _undesigned experiment within an experiment_. Analogy.