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t 



332 



LAWS OF VARIATION. 



Chap. XXV 



renal capsules (of which the functions 



-~™ -puira ^ui wmcn tne tunctions are unknown), the skin 

 becomes bronzed ; and in hereditary syphilis, both the milk and 



the second teeth 



assume a peculiar and characteristic form 



Professor Rolleston, also, informs me that the iucisor teeth 



sometimes furnished with 



a 



rim 



phtl 



pulmonary deposition of tubercles 



In other cases of 



i^ S1 ! and ° f Cyanosis the nails and finger-ends become 

 clubbed like acorns. I believe that no explanation has been 

 ottered of these and of many other cases of correlated disease. 



What can be more curious and less intelligible than the fact 

 previously giv< 



young pigeons 



on the 



ity of Mr. Tegetmeier, that 

 of all breeds, which when mature have white. 



yellow, silver-blue, or dun-coloured plumage, come out of 



egg almost naked ; whereas pigeons of other colours when first 



White Pea-fowls, as has 

 England and France, 30 and as I have 



born are clothed with plenty of 



be 



observed both 



myself seen, are inferior in size to the common coloured kind, 

 and this cannot be accounted for by the belief that albinism is 

 always accompanied by constitutional weakness ; for white or 



albino moles are generally larger than the common kind 



To turn to more important characters : the niata cattle of the 



Pamp 



remarkable from 



short foreheads, upturned 



muzzles, and curved lower jaws. In the skull the nasal and pre 

 maxillary bones are much shortened, the maxillaries are excluded 

 from any junction with the nasals, and all the bones are slightly 

 modified, even to the plane of the occiput. From the analogical 

 case of the dog, hereafter to be given, it is probable that the 

 shortening of the nasal and adjoining bones is the proximate 

 cause of the other modifications in the skull, including the 

 upward curvature of the lower jaw, though we cannot follow 

 out the 'steps by which these changes have been effected. 



Polish fowls have a large tuft of feathers on their heads : and 



their skulls are perforated by numerous holes, so that a pin 



be dr 



the 



brain without touching any bone 



That 



this deficiency of bone is in some way connected with the tuft 

 of feathers is clear from tufted ducks and geese likewise having 



3 ° Rev. E. S. Dixon, 'Ornamental Poultry,' 1848, p. ill; Isidore Geoffroy, 

 'Hist. Anomalies,' torn. i. p. 211. 



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