I have referred in a previous chapter to the value of leather waste as a fertilizer. Five years ago we did not pursue this problem along determined lines, mainly because we did not really understand its preparation, while our farmers did not regard the product then marketed with favour. But to-day there is a welcome change both in productive methods and the agricultural attitude. Some large plants for the treatment of the leather waste have been laid down and are being brought into operation. Two distinctive treatments are being followed. In the one instance the curried leather--sheer residue from the boot factories possessing no other possible use--is being submitted to treatment for the extraction of the greases and fats used in the dressing processes. In the second system these fats, owing to their low grade and as yet absence of possible industrial use, are being ignored, although they disappear for the most part from the product in the course of treatment. Otherwise the two methods are broadly identical. The leather is carbonized and then reduced to a dark greyish powder. In this form it meets with the full approval of the farmer, and, as its nitrogen content is said to range up to 9 per cent., it is meeting with ready disposal, the demand at the present moment being far in excess of supply. At one works an output of 60 tons a week is being recorded, which incidentally indicates the quantity of leather waste incurred in our boot-producing factories. I have also drawn attention to the extent to which fish scrap is now being treated, and here again highly satisfactory developments are to be narrated, the trade, especially in regard to the production of fertilizer, being in a flourishing condition. Fish guano appeals to the farmer, owing to its high content of ammonia and phosphate which aggregate approximately 20 per cent. At one fish waste reducing factory the output is 20 tons every 24 hours, the plant being run on continuous lines, but arrangements are being completed to double the capacity to secure an output of 40 tons during the 24 hours. Hitherto the farmer has not been completely enamoured of fish manure because in certain instances, notably in the treatment of the oily fish, such as the herring, the grease content, which was as anathema to him, was somewhat heavy. But the perfection of the solvent extraction process which I have described, and whereby the oil contained in the finished fertilizing meal can be reduced to as low as 1 per cent., has completely removed this disability.