NOTES ON THE HAIR-SLOPE IN MAN. 307 



applied to each. In accounting for " radiating whorls," he goes 

 to the vegetable kingdom for analogies, and refers to the law of 

 spirals and screw forms found in leaves, branches, stems, flowers, 

 and certain allied phenomena, for support of his views. 



It will be seen that the views of Eschricht and Voigt as to 

 the direction of hair on the body of Man have an allied basis — 

 viz., the necessary arrangement of the hair in most complicated 

 ways, entailed by the special anatomy of this particular species. 

 For them the arrangement follows as a matter of course, and in 

 all cases. It is easy to see that Voigt's theory may fit the facts 

 •closely, and it is ably worked out. But it is also easy to see 

 that the fundamental position — viz., that the stretching of the 

 skin produces the change of position of the developing hair- 

 germ from the perpendicular to the sloping direction, and that 

 this depends for its variations upon the contiguous anatomy — is 

 not necessary. On a surface such as that of the human embryo, 

 subject, even before its birth, to constant slight pressure, and 

 much more so in after life, no other than a sloping direction of 

 that portion of the hair which is external to the follicle could 

 occur. If this be so, the portion within the follicle would of 

 necessity be drawn in a sloping direction also. This considera- 

 tion as to the general cause of the slope of hair would render 

 Voigt's theory unnecessary, however ingenious the particular 

 applications of that theory may be as to certain modifications 

 found in many regions. But as a matter of fact they do not fit 

 in all respects those varieties found in Man, and certainly not 

 in the very numerous variations of hair-slope found in other 

 animals, as I have shown elsewhere. To take an instance in one 

 particular animal. The Mole, being a vertebrate and a mammal, 

 has sufficient resemblance in type of structure to Man or the 

 lower animals to require that it should share as to its hair-slope 

 in the results claimed as being produced in Man by the develop- 

 ment of the anatomy of Man, and the effect on the hair-follicles 

 of its skin. But, as is well known, the skin of this animal 

 possesses that unusual quality of hair resembling velvet, and has 

 no fixed slope of hair as is the case in most other animals, for 

 the simple reason, it may be presumed, of its burrowing habits. 



In the case of Man it is conceded that most, if not all, of the 

 directions of slope found in the foetus are also found to continue 



