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Harris, who expanded the dodtrine of Sylerus, and who from 

 his high rank and fuppofcd fuccefs in practice brought this 

 do6irine into great fafhion in England, fays, " ^wd viridis 

 " faciim color acido bill admi'xto fe prorfus debeat, objervationi plane 

 " fenjib'ili illorum, qui expen'ri amant coloruin in viridem mutationes 

 ' ' acelo etjpiriiibus acidis perficiendas, evidentij/lme apparebit" Having 

 already found many affcrtions equally pofitive to be erroneous, 

 J determined to doubt every thing advanced on thefubjed; I 

 therefore procured fome bile from the gull bladder of a foetus 

 which was deprived of life in the birth ; it was of a deep 

 yellow colour and thick conliilence. After diluting fome of 

 this bile with milk, I gradually dropped into it fome ftrong 

 vinegar without being able to perceive the leaft change of colour; 

 ■whereas on adding nitrous acid, even in very fmall quantity, 

 to a portion of the fame diluted bile, it immediately changed 

 it to a deep green. This experiment I repeated in prefence of 

 fome of the pupils of the Lying in-Hofpital with precifely the 

 fame event. I fliould not venture to ftate two experiments as 

 proof in any doubtful cafe, did I not find them confirmed by 

 Dr. Maclurg, the lateft and moft accurate experimenter on this 

 fubjed. In the firft eight experiments * on human cyftic bile, 

 this author endeavours to afcertain the efFeds of mineral acids 

 on bile ; thefe he found, when applied ftrong, united with it 

 and diflblved it in a fhort time, with fome variations of the 

 phienomena, producing a fine green colour. 



* See an analyfis of Dr. Maclurg's experimental enquiry on bile in the Edinburgh 

 Medical Commentaries. Vol. ift, p. 150. 



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