TBANSACTIONS OF SECTION B. 723 



5. Report on Solution. — See Reports, p. 438. 



6. A Discussion on the Present Position of Bacteriology, more especially in 

 its relation to Chemical Science, was opened hy Professor Pekcy F, 

 Fkankland, F.B.S. 



Professor Feankland's paper was ordered to be printed 

 in extenso among the Reports. — See Reports, p. 441. 



7. RemarJis on the Chemistry of Bacteria. By R. Warington, F.B.S. 



8. On Fermentation in the Leather Industry. By J. T. Wood. 



The science of bacteriology touches upon the leather industry in the following 

 important points : — 



1. Putrefaction. 



2. The Soaks. 



3. Changes in lime liquors. 



4. Bating or ' Pining.' 

 6. Drenching. 



6. Fermentation of tan liquors. 



The author only gave a short resume of our present knowledge of the ' drench- 

 ing ' process, as this closely resembles ordinary fermentations. 



Skins from the bate after washing are placed in vats containing an infusion of 

 bran in water (0-4 to 1 per cent, of bran) at a temperature of 30° to 35° C. This 

 ferments vigorously for eighteen to twenty-four hours with evolution of consider- 

 able quantities of gas and the formation of weak organic acids, which have a 

 slight swelling action on the skin, cleanse the pores, and make it in a fit condition 

 to receive the tannin. On examination with a high power of the microscope the 

 liquid is found to be swarming with active bacteria. They are mostly in the form 

 of pairs or dumb-bells, each cell 0'75jLt x 1-25/i ; some form chains. I described ' a 

 method by which the organism causing the fermentation was separated, as it re- 

 fused to grow in ordinary nutrient gelatine, and lately, in conjunction with Mr. 

 W. H. "Willcox, B.Sc, have made a complete examination of the products of the 

 actual fermentation as it takes place in the works, previous to carrying out a 

 similar research with the pure ferment. 



We found the following gases evolved : — 



A is from a vat containing no skins, one to two days. 



B from a vat containing skins, two to three days. 



from a vat containing skins, three to four days. 



The H„S is present only in small quantities (1 to 2 per cent.). 



The principal acids found were acetic acid and lactic acid, accompanied by 

 small quantities of formic acid and butyric acid. 



The following table shows the quantities found in an experimental drench per 

 1,000 c.c. :— 



' Journ, Soc. CTiem. Ind., ix. 27. 



3 A 2 



