Sentence:  It was a horrible smell of corrupt flesh and mouldy bones, mingling with the sickly steam of from cauldrons in which the anatomized animals were seething down. None save those who have been so unfortunate as to venture upon the confines of a <WSD>knacker's yard</WSD>, can possibly conceive the horrible nausea produced by these blended effluvia: it was enough to make the strongest stomach heave and become sick. 
Meaning of the word marked with <WSD> tags:  The area of a slaughterhouse where carcasses unfit for human consumption or other purposes are rendered down to produce useful materials such as glue.