In order to ensure uniform results a pure culture of the special bating bacteria is supplied with every 5 kilos of the erodin powder. The weighed amount of erodin is placed in a perfectly clean mashing-tub, with 50 times the weight of water at a temperature of 40° C. a pure culture of Bacillus erodiens is added to the mixture, and the whole covered with a clean cover and allowed to stand for two or three days. A little steam is admitted morning and evening so as to maintain the temperature at about 40° C., or some other suitable device for heating is applied. Several tubs may be kept in a small stove heated to the right temperature by steam pipes. In this way the bating bacteria develop rapidly, and if the proper precautions as to cleanliness and temperature have been observed, there is no fear of any adventitious germs getting the upper hand. As soon as a vigorous growth is attained, usually on the third day, the bate is ready for use. Erodin is in use on a fairly large scale, and, as is usually the case, difficulties have arisen on a manufacturing scale which do not occur in the laboratory. In the practical application of the material the mashing-tub may be 3 ft. 9 in. in diameter and 3 ft. 3 in. in height and of a capacity of 200 galls. Steam is admitted directly by means of a copper pipe fitted with a boiling jet. The goods are bated in the ordinary bating paddle or puer wheel (Fig. 3, p. 13). During the year 1901 about 9000 dozens of sheep “grains” were puered with Erodin at Trent Bridge Works (Messrs. Turney Brothers, Ltd.) Nottingham, and considerable experience gained in its use. The mode of operation was as follows:--On Fridays 30 kilos of Erodin powder was mashed in a wooden vessel in 1600 litres water at 40° C. and inoculated with a sufficient quantity of a pure culture of B. erodiens. The temperature was kept at 35°–40° C. by admission of a little steam first thing in the morning, again at noon, and in the evening, and the liquid so prepared was ready for use on Monday. One wheel or paddle was kept going for the work. To start the operation, 200 litres of stock liquor was put into the wheel, and sufficient water added for the goods to turn freely. The skins previously washed, as described in Chapter I., were paddled until sufficiently “fallen” or “down.” For the following lots, the liquor was strengthened by the addition of 100 to 140 litres of the stock liquor, the wheel being run off and cleaned out once a week. The general result showed that “high-limed” skins and previously salted skins were more refractory to this bate than to dung.