Pi^V^ 



a 



mor 



326 LAWS OF VARIATION. Chap. XXV. 



to twelve inches in length ; so that cnrliness and shortness of 

 the hair are here, as with the negro, apparently correlated. 



With respect to the horns of sheep, Yonatt » remarks that 

 " multiplicity of horns is not found in any breed of much value : 



it is generally accompanied by great length and coarseness of 

 « the fleece. Several tropical breeds of sheep which are clothed 

 with hair instead of wool, have horns almost like those of a goat. 

 Sturm 12 expressly declares that in different races the 

 wool is curled the more the horns are spirally twisted. We have 

 seen in the third chapter, where other analogous facts have been 

 given, that the parent of the Mauchamp breed, so famous for 

 its fleece, had peculiarly shaped horns. The inhabitants of 

 Angora assert » that « only the white goats which have horns 

 " wear the fleece in the long curly locks that are so much 

 " admired ; those which are not horned having a comparatively 

 " close coat." From these cases we may conclude that the 

 hair or wool and the horns vary in a correlated manner. Those 

 who have tried hydropathy are aware that the frequent appli- 

 cation of cold water stimulates the skin ; and whatever stimu- 

 lates the skin tends to increase the growth of the hair, as is well 

 shown in the abnormal growth of hair near old inflamed surfaces. 

 Now, Professor Low 14 is convinced that with the different races 

 of British cattle thick skin and long hair depend on the hu- 

 midity of the climate which they inhabit. We can thus see 

 how a humid climate might act on the horns—in the first place 

 directly on the skin and hair, and secondly by correlation on 

 the horns. The presence or absence of horns, moreover, both in 

 the case of sheep and cattle, acts, as will presently be shown, by 

 some sort of correlation on the skull. 



With respect to hair and teeth, Mr. Yarrell 15 found many of 

 the teeth deficient in three hairless "^Egyptian " dogs, and in a 



hairless terrier. The 



and premolars suffered 



most, but in one case all the teeth, except the large tuber 

 cular molar on each side, were deficient. With man several 

 striking cases have been recorded 16 of inherited baldness with in- 



12 ^t f ieeP ' P ' U2 ' British Islands >' PP- 3 <>7, 368. 



leo- Ea cen, Kreuzungen, &c.,' " 'Proceedings Zoolog. Soc.,' 1833, 



182o, s. 24. p 113 



_ Quoted from Conolly, in « The i« Sedgwick, < Brit, and Foreign 



Indian Field,' Feb. 1859, vol. ii. p. 266. Medico-Chirurg. Review,' April, 1863, 

 14 « Domesticated Animals of the p. 453. 



