110 THE GROWTH OF THE HOOF. 



lively controversy. The principal views on the point are as 

 follows : — 



(1) The sensitive wall only produces the laminal sheath of 



the horn wall. This is the generally accepted view, 

 and is supported by H. Bouley and Leisering. 



(2) The sensitive wall produces the entire mass of cement 



substance or inter- tubular horn (Fuchs). 



(3) The sensitive wall produces the inter-tubular horn of the 



inner (white) sheath of the wall (Brauell). 



(4) The sensitive wall has no part in the production of 



horn laminae, but the entire wall, including the 

 lamina, grows downwards from the coronet. The 

 sensitive wall produces a fine layer of horn lying 

 between the laminie and the mucous sheath of the 

 sensitive laminae. This view appears untenable, if 

 only because it fails to explain the gradual increase 

 in width of the horny lamimv as one proceeds from 

 above downwards. 



