In an experiment with twenty-four Large White pigs fattened from weaning to bacon weight on a diet containing either 5 or 9% of dried Clostridium residues the latter was found to be an efficient protein supplement.

The authors wish to express their thanks to Dr S. J. Rowland who made all the chemical analyses involved, to the Directors of Commercial Solvents G.B., Ltd., who kindly supplied the product, and to Mr E. Gill, Works Manager of the above Company, for helpful collaboration.