ZOOLOGICAL DISTRIBUTION OF DISEASE. 259 



joint ends of bones. Rheumatic gout, or, as it is now 

 more appropriately termed, osteo-arthritis, is a disease 

 of great interest, for it has a wide zoological distribution, 

 and has even been detected in the joints of the extinct 

 Irish Elk (Megaceros hibernicus}. This disease is cha- 

 racterized by enlargement of the ends of bone, destruc- 

 tion of the cartilage and synovial membrane of joints, 

 with calcification of the ligaments. It is no respecter of 

 persons ; young and old, rich and poor, high and low, 

 suffer from it. I have detected the disease in the joints 

 of a snake's backbone, in birds of various kinds, including 

 the neck of an ostrich, in cats, dogs, leopards, lions, 

 tigers, horses especially, oxen, sheep, kangaroos, bears, 

 and many others. It is as far as I can ascertain the 

 most widely diffused of all the bone diseases to which 

 vertebrated animals are liable. 



In order to show the care necessary in such generali- 

 zations we may take the recent additions to our know- 

 ledge of such a long recognized disease as cretinism. 

 All visitors to Switzerland, the Rhone and Aosta valleys, 

 are familiar with what is termed endemic goitre and 

 endemic cretinism. The leading features of cretinism 

 are briefly these : The disease' is congenital, and dis- 

 plays itself in unnatural shortness of the trunk and 

 limbs, malformations of the skull (as a rule it is unusually 

 small), and idiocy, combined with abnormal conditions 

 of the thyroid body. Cretins, as those affected with 

 this disease are called, present a characteristic appear- 

 ance ; a typical cretin is represented in fig. 126, taken 

 from the admirable report, compiled by a Commission, 

 created by the King of Sardinia, to inquire into this 



