ZOOLOGICAL DISTRIBUTION OP DISEASE. 265 



Cretinism has a wider distribution, geographically and 

 zoologically, than we were aware even twenty years ago, 

 and it is not unreasonable to suppose that careful 

 inquiry will show that many other similar diseases, 

 supposed to be rare or confined to certain districts, are 

 as a matter of fact commoner than we suspect. 



Rickets is another example of a disease having a 

 wide zoological distribution. The leading characters 

 of rickets are, undue softness of bone in young animals, 

 associated with catarrh of the stomach and intestines, 

 depending upon, or induced by, unsuitable food and 

 unfavourable surroundings. The softness of the dif- 

 ferent parts of the skeleton gives rise to a complicated 

 series of deformities, some of which are incompatible 

 with life. 



For a long period rickets was supposed to be re- 

 stricted in its distribution to England, and is, to this 

 day, often referred to as the English disease. Now, we 

 know that rickets occurs all over Europe and in other 

 parts of the world, and recently I had an opportunity 

 of examining portions of a rickety skull which were 

 obtained from Lamoo, an island near Zanzibar ; it was 

 found buried in sand, on the site of an old battle-field, 

 by Dr. Briscoe. 



Rickets is so very common in man that a priori we 

 should expect it to be frequent in other members of 

 man's class. On this head we, possess but scanty infor- 

 mation. Mammalian skeletons have been preserved in 

 museums, and erroneously labelled ; we now know that 

 most of them are rickety skeletons, for the systematic 

 inquiry which I have conducted into the diseases of 



