AbstractsBiology & Animal Science

"This investigation was undertaken because there is very little definite information in print, regarding the micro-organisms which play such an important part in the Old Dutch Process for manufacturing white lead. The statements concerning this process are very general in character. For instance, one book states, "The first action which goes on is to convert blue lead into basic acetate of lead. This is brought about by the heat of the fermenting tan, causing the evolution of acetic acid from the liquid of the pots." Albert H. Hooker in a little treatise on white lead says: "As it stands now, the tan bark pile, with its vital fermentation, is treated much as mother made caks [sic]; usually it came out fine, but sometimes it fell, heavy as lead, no one knew why. As it is now, no one seems to know whether this fermentation is due to a yeast, an enzyme, or to bacteria, or, given the cause, what are the conditions which will produce the most satisfactory yield, both of carbon dioxide gas and of heat during the desired period. It seems generally known that hot water or excessive heating will "kill" the tan but beyond that little is known." It would therefore appear that very little attempt has been made to investigate the process from a bacteriological point of view" – Foreword, p. 1.