8 ANIMAL PROTEINS 



of the heavy leather industries. In a very narrow sense 

 the term is also sometimes applied only to ox hides, 

 which for most heavy leathers are the ideal raw 

 material. 



The Home Supply of hides forms a large important 

 proportion of the total raw material. Its importance, 

 moreover, is rapidly increasing, for the excellence and 

 abundance of the home supply determines the extent to 

 which it is necessary for the industry to purchase its raw 

 material abroad. The position of our national finances 

 makes this an increasingly serious matter, for hides are 

 comparatively a very expensive material. 



The quality of our home supply of hides is very valu- 

 able, being determined by the conditions of the animal's 

 life, its precise breed, and by other factors such as age 

 and sex. The best hides are usually obtained from animals 

 which have been most exposed to extremes of wind and 

 cold, as such conditions tend naturally to develop a thicker 

 and more compact covering. Broadly speaking, these 

 include the hides from cattle of the northern and hilly 

 districts. The age of the animal when killed is also a 

 dominating factor. Calf skins are very soft, fine grained 

 and compact, the state of rapid growth favouring the 

 existence of much interfibrillar substance. The youngest 

 animals supply suitable raw material for various light 

 leathers (see Part II., Section V., p. 120), and are also very 

 suitable for chrome work (see Part III., Section III., p. 156). 

 Bull and cow hides, on the other hand, are from animals 

 whose growth is complete, and show in consequence a lack 

 of interfibrillar substance, coarse fibres and a rough and 

 often wrinkled grain. The resulting leather tends conse- 

 quently to be spongy, thin, empty and non- waterproof. 

 Intermediate between these extremes are the hides of the 

 ox and heifer, large, yet of good texture, and well supplied 

 with interfibrillar substance. These hides are much the 

 best for sole leather, a firm, smooth-grained and well-filled 

 leather being needed. The term " kip " is often applied 

 to small hides and to hides from large calves. In the 



