EXPERIMENTAL 127 



been employing harness on his friend and servant, thus making the 

 essential conditions for an experiment of which he and his servant 

 were alike unconscious, that is to say, he influenced a growing 

 living structure, the horse's hair, by the artificial force of pressure, 

 applied to the coat at various points. These varied from age to 

 age as to fashion and material, and the present full development 

 of harness of a draught horse was probably slow in coming. 



Examples of the Effects of Pressure. 



Looking at the figures of a horse harnessed, and another 

 without harness, Figs. 49 and 50, one sees on the latter eight different 

 regions where patterns of hair, not found in the horse normally, 

 are displayed. They are as follows : — 



A. The under surface of the neck. Pattern due to the collar. 



B. The hamstring region. Pattern due to the kicking 



strap. 



C. The hollow corresponding to Pattern due to strap of 



what we should call the saddle, 

 armpit. 



D. The coccygeal or tail -region. Pattern due to the crupper. 



E. The side of the neck. Pattern due to the reins. 



F. The shoulder. Pattern due to the shaft. 



G. The side of the face. Pattern due to strap of 



head stall. 

 H. The border of the neck under Pattern due to collar. 



the collar. 

 All these aberrations from the normal are rare except the first 

 (a), and all are based on the observation and drawing of individual 

 specimens which I brought before the Zoological Society and 

 the details of which are given in a note on page 130. The 

 rarer seven examples are described because taken together they 

 show what the pressure of harness can do at certain points 

 where its pressure is adequate, and they are all situated where they 

 might be expected if such a force could effect hair-changes, and there 

 are none of them found on areas where neither pressure nor under- 

 lying muscular traction can act efficiently. Thus in many thousands 

 of horses I have never seen a hair-pattern on the middle of the flank 

 or the under surface of the abdomen or the middle of the back or 

 gluteal region or on the fore or hind legs. This negative evidence 

 is of great importance, and must be taken for what it is worth. 

 I may venture to remind the reader that every one of these pheno- 

 mena is an artificial product of man's treatment of the horse. They 

 come thus under the category of undesigned experiments. 



