The present volume is the outcome of a desire to preserve the numerous notes which I have made during over twenty years’ work at the practical and scientific study of bating. It has been my wish to complete the investigation of this important process in leather manufacture, for, as Lord Allerton has paradoxically remarked:1 “Good leather is made before the skins go into the tan liquor at all,” but owing to circumstances having drawn me more and more to the commercial side of the business, I have been compelled to abandon this project.

When learning the trade as an apprentice every fault in the leather was attributed to this part of the work, and the troubles and miseries of the “puer shop” first caused me to take up the study of puering. I was determined to know the causes underlying the process. Puering is not only a filthy and disgusting operation, but is prejudicial to health, and in the nature of it is attended by more worry and trouble than all the rest of the processes in leather making put together.

By giving a rÉsumÉ of the work done up to the present time, I hope to be of assistance to the younger generation of Tanning Chemists, to some of whom is reserved the privilege of carrying on the work.

I think it may now be said, at any rate, that the solution of the problem of constructing an artificial bate on scientific principles, which will replace the present crude methods, is well within sight. The principal obstacles are, on the one hand, the inertia of English manufacturers; on the other hand, the class of labour employed in puering is not of the highest order of intelligence. Innovations in most things are resisted, partly because they necessitate changes in the method of working, and partly because of the innate conservatism of human nature. It is certainly a significant fact that although most of the pioneer work on this subject was done in England, the practical side has been taken up in Germany, and by freely spending money on large trials in the works they have enabled the manufacture of artificial bates to be developed on a commercial scale.

In 1886, while studying Chemistry under Professor Frank Clowes, I began to examine microscopically the various liquors of a light leather factory, and more especially the bran drenches. At that time I knew nothing of bacteriology, for the simple reason that little but pathological work in this line was being done in England. Through the kindness of Professor Clowes, I obtained an introduction to Mr. Adrian Brown (now professor at the University of Birmingham), and in his laboratory at Burton-on-Trent I saw the first pure cultivations of Bacterium Aceti which he had isolated, and of which he had completely studied the chemical action.2 I had there an opportunity of seeing the methods and apparatus employed. I also had the benefit of Mr. Brown’s advice in commencing a systematic study of the process of drenching. Professor Percy Frankland, then at Dundee, advised me further as to the microscope and other matters. My warmest thanks are due to these friends for directing me in the right way.

As a result of my first investigations, on December 11, 1889, I read a short paper entitled “Methods of Bacteriological Research—with some account of Bran Fermentation,” before the Society of Chemical Industry.

The way in which this paper was received led to a further research into the nature of bran fermentation in conjunction with Mr. W.H. Willcox, B.Sc. (now Senior Analyst to the Home Office), by which the action of the bran drench was thoroughly investigated, and the results published in the Journal of the Society of Chemical Industry, May 31, 1893.

This was followed, on June 30, 1897, by a paper “On a Pure Cultivation of a Bacillus Fermenting Bran Infusions,” also in conjunction with Dr. Willcox.

In 1898, in reply to a publication of Director Eitner, of Vienna, I published in the Leather Trades’ Review (November 15), a rÉsumÉ of the whole subject, entitled “The Rationale of Drenching.”

Already, in the first paper above named (“Methods of Bacteriological Research”), I had called attention to the bacteria of the bate prepared from dogs’ dung, and in a paper entitled “Fermentation in the Leather Industry,”3 developed this aspect of the subject, and first pointed out the influence of enzymes in bating. I therefore decided to study the phenomena occurring in the bate in the same way as I had studied drenching.

The work was begun in 1895, and, as it was likely to occupy an indefinite time, the first instalment, entitled “Notes on the Constitution and Mode of Action of the Dung Bate in Leather Manufacture,” was published November 30, 1898; while “Further Notes on the Action of the Dung Bate” was published on November 30, 1899.

In these papers I indicated the lines on which a culture of bacteria might be practically applied to the bating of skins, and gave the composition of a liquid which, while acting as a nutrient medium for the bacteria, contained at the same time most of the active chemical compounds of dog dung.

Meanwhile, Dr. Popp and Dr. Becker, in Frankfort a/M, were investigating independently the bacteria of dog dung, and conceived the idea of employing them commercially. My dear friend Franz Kathreiner, of Worms,4 put me in communication with these gentlemen, and we were thus enabled to work in conjunction. As a result of our combined labours, an artificial bate, called “Erodin,” was put upon the market. This will be fully treated of in the chapter on Artificial Bates.

I shall give first a short account of bating, and then sum up as briefly as possible the present state of our knowledge of the process, afterwards giving an account of the more important of the various patents which have been taken out for artificial bates.

Although the book is divided into separate sections for convenience, it is obvious that we cannot separate chemistry from physics, nor bacteriology from chemistry, nor enzyme action from all three.

My own papers are printed as read. The Bibliography does not profess to be complete, but includes most of the works consulted.

No one realizes more than I how incomplete the work is, and how much research still remains to be done in order to complete it.

Thanks to the efforts of the Leather Industries Department of the University of Leeds, and the Technical College of the Leather Sellers’ Company, Bermondsey, the era of Rule of Thumb is passing, and there is little doubt that the work that is being done in these institutions will be translated into practical use in the factories by the coming generation.

I wish to express my special thanks to Mr. Douglas J. Law, and to Dr. H.J.S. Sand for assistance in preparing the notes for publication, to Dr. J. Gordon Parker, Director of the Leather Sellers’ Technical College, London, for the description of the bating of hides, and to Professor KrÀl, of Prague, for some of the photographs of bacteria.

JOSEPH T. WOOD.

Nottingham : January 1912.