ZOOLOGICAL DISTRIBUTION OF 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 @ przorz 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 
