78 ANIMAL PROTEINS 



down. The old limes are, of course, mellower than the new 

 and exert the desired softening effect. The working is 

 quite analogous to that of a round of handlers. Unhairing 

 is sometimes assisted by the use of arsenic sulphide. E.I. 

 kips need a thorough soaking before any liming ; several 

 days are usually needed. The old methods involving 

 putrid soaks and stocks may be considered out of date, and 

 it is usual to soften back in caustic soda or sulphide soaks 

 with some assistance by drumming. A little sulphide is 

 sometimes added to the older limes to continue the treat- 

 ment. 



The goods are next thoroughly bated and delimed. The 

 hen or pigeon dung bate is still usual, and probably gives 

 the best results, though closer approximations have been 

 made of recent years on artificial lines. Some bating with 

 solution of hide substance seems necessary for these goods. 

 The lighter goods are often drenched also to complete the 

 deliming, using 6 per cent, bran on the weight of pelt. The 

 heavier goods are more often treated with boric acid after 

 bating, which not only delimes completely and gives a soft 

 relaxed felt, but also acts as antiseptic and stops the action 

 of the bate, a matter of some importance (see Section II.). 

 Lactic acid may substitute boric, in which case about 

 2 per cent, on the pelt weight of 50 per cent, acid 

 may be required. It is important to avoid a strong 

 solution and local excess, hence lactic acid must be added 

 gradually so that the liquor is never stronger than 0*2 

 per cent. Drumming and paddling is an advantage in 

 deliming. 



The tannage is light in most cases, partly because some 

 of the finished goods are sold by area, but partly also 

 because even if sold by weight, the weight is obtained 

 quicker and more easily by stuffing, which course is also 

 often preferable to obtain the desired mellow feel, water- 

 proof ness and durability. Hence it is seldom that strong 

 liquors are employed. The tannage is also mellow, on ac- 

 count of the softness and pliability required ; no acids are 

 consequently employed, and no material which is liable to 



