Liming chrome leather satisfactorily is almost an impossible ideal. Every conceivable arrangement has some objection to it. The time of the process may be shortened either by the use of sulphide or by the use of mellow or old limes. To shorten time by the use of sodium sulphide unfortunately involves the employment of more alkali than is desirable, with a consequent plumping effect and tendency to harshness. If sufficient sulphide be used to make the liming very short, then the grease is not "killed" (saponified or emulsified). If the harshness and alkalinity be removed by using also an excess of calcium chloride, then the lyotrope influence of this substance enhances the solation of the hide gel. On the other hand the use of old lime liquors avoids the plumping effect, but increases considerably the bacterial activity, and the bacterial enzymes produce both hydrolysis and solation of the pelt. In practice what is generally done is to shorten time by both methods and so to admit both disadvantages to a limited extent. This is theoretically more sound than would appear, for in mellow limes sulphide has less plumping power but is just as strong a depilatant; whilst, on the other hand, a mellow liming shortened by sulphide is less objectionable as there is some evidence that bacterial activity is relatively less in the first few days. Hence a mellow sulphide liming of 7-10 days is very common in practice, but sometimes a 3-4 days' process with more sulphide is also found satisfactory. It would seem probable that the real solution of the problem would be found by a different process altogether. In this connection it is interesting to note that a Continental proposal to unhair by enzyme action only has been found most practicable with goods for chrome, and, in the author's opinion, some development on these lines, in which a lipolytic enzyme is used in addition to a proteolytic, might solve the difficulty, and give a rapid depilation which dispenses with liming, plumping and deliming with the consequent loss of valuable hide substance. In the usual short, mellow, sulphide liming it is clear that there is not much advantage in a "round" or "set" of pits. Hence the one-pit system is popular on account of the less labour involved. The above remarks are less applicable in the case of chrome sole leather. In this case weight is a great consideration and plumping is necessary. In such leather the chrome tannage is supplemented by the use of waxes, which fill up the spaces between the fibres and give solidity and waterproofness to the finished article. With this leather an ordinary sole leather liming in sharp liquors is not unsuitable, handling the goods from "mellow to fresh," but there is, on the whole, a tendency to shorten the process to about a week by using more sulphide.