Of the developmental history of the lower organs of 

 sense I have but little to say. The development of the skin- 

 covering, which is the organ of the sense of pressure (sense 

 of touch) and of warmth, we have already traced (p. 209). 

 I need only add that in the leather skin (corium) of Man, 

 as of all higher Vertebrates, innumerable microscopic sense- 

 organs develop, the direct relations of which to the sensa- 

 tions of pressure or resistance, of warmth and of cold, arc 

 not yet ascertained. These organs, in or upon which the 

 sensitive skin-nerves terminate, are the so-called " touch 

 bodies " and the " Pacinian bodies," named after their dis- 



