_Judgment after Scudding._--All lots well down; E 47 whitest colour; all smooth grain, E 47 and B 3 smoothest. The 3 goat were not low enough. It was observed both in laboratory experiments[139] and in practical work that the presence of solid matter in the puering liquor had a considerable influence on the speed at which the goods fell. The clearer the liquor the slower the action. The explanation of this fact is not quite clear. Possibly the finely divided solid matter acts as a carrier for the enzymes, each particle offering a very extended surface, or it may be that the action of the solid matter is mechanical, like that observed in bran drenching. [139] J.S.C.I., 1899, p. 910. See also p. 73. The goods puered with erodin, whether split or unsplit skins, should be scudded on the grain. Sheep splits are scudded with a machine of Sir John Turney’s type. (Fig. 6, p. 17.) Roans and goat may be scudded with any of the spiral knife machines (Turner, Mœnus, etc.) in general use. The following figures, p. 187, giving the reactions of an erodin bate in c.c. N/5 alkali or acid required to neutralize 50 c.c. filtered bate, are of interest as being taken from actual work. They were kindly communicated to me by Herr Karl Schorlemmer, chemist to Messrs. Doerr and Reinhart, of Worms. Erodin, tested by the electrometric method, was found to have the following hydrogen ion concentrations:--Paddle before goods, π = 0·672 volt, equivalent to a hydrogen ion concentration p_{H+} 6·6. The same liquor after goods, π = 0·710, equivalent to p_{H+} 7·3. Compare puer liquors, p. 79. ---------------+--------------+------------- Bate | Before Goods | After Goods ---------------+--------------+------------- 1. Old | 0·05 alkali | 0·4 acid 2. Fresh | 0·15 " | neutral 3. Old | 0·05 " | 0·55 acid 4. Fresh | 0·2 " | 0·05 " 5. Old | 0·1 " | 0·1 " 6. Fresh | 0·45 " | 0·15 alk. 7. Old | 0·15 " | 0·3 acid 8. Fresh | 0·5 " | 0·1 alk. 9. Old | 0·1 " | 0·3 acid 10. Fresh | 0·3 " | neutral 11. Old | 0·1 " | 0·7 acid 12. Fresh | 0·2 " | 0·05 alk. 13. Old. | 0·1 " | 0·25 acid 14. Fresh | 0·4 " | 0·15 alk. 15. Old. | 0·05 " | 0·3 acid 16. Fresh | 0·45 " | 0·1 alk. Mean of old | 0·087 " | 0·31 acid Mean of fresh| 0·33 " | 0·051 alk. ---------------+--------------+------------- *Oropon.*--An interesting application of the theory of the bating process which was put forward by me[140] is that of Dr. Otto Röhm[141] in 1908, in which, instead of a bacterial culture, he employs an infusion of pancreas in conjunction with ammonium salts. This bate has been put upon the market in the form of a powder under the name of Oropon.