Sentence:  When, in 1858, Joseph Lister amputated the right leg of a six-year-old girl suffering from gangrene, he noted that the <WSD>autochthonous</WSD> blood clot extended down the anterior tibial artery as far as the commencement of the gangrene. 
Meaning of the word marked with <WSD> tags:  Originating where found; found where it originates.