Class II. i. 6. 7. OF SENSATION. t 4 $ 



« 3. Pus is difmfible through a diluted vitriolic acid, though 

 mucus is not 5 the fame occurs with water, or a folution oi fea 

 fait. 



« 4. Nitrous acid dijTolves both pus and mucus ; water added 

 to the folution of pus produces a precipitate ; and the fluid a- 

 bove becomes clear and green ; while water and the iolution of 

 mucus form a dirty coloured fluid. 



" 5. Alkaline lixivium diflblvcs (though fometimes with diffi- 

 culty) mucus, and generally pus. 



" 6. Water precipitates pus from fuch a folution, but does not 

 mucus. 



« 7. Wliere alkaline lixivium does not diiToIve pus, it ftill dif- 

 tinguiihes it from mucus j as it then prevents its diirulion through 

 water. 



" 8. Coagulable lymph is neither foluble in diluted nor con- 

 centrated vitriolic acid. 



" 9. Water produces no change on a folution of ferum in al- 

 kaline lixivium, until after long (landing, and then only a very 

 flight fediment appears. 



" ig. Corroiive fubiimate coagulates mucus, but not pus. 



u From the above experiments it appears, that ftrong vitri- 

 olic acid and water, diluted vitriolic acid, and caultic alkaline 

 lixivium and water, will ferve to diftinguim pus from mucus ; 

 that the vitriolic acid can feparate it from coagulable lymph, and 

 alkaline lixivium from ierum. 



« And hence, when a perfon has any expectorated material, 

 the competition of which he wifhes to afcertain, let him diflblve it 

 in vitriolic acid, and in cauftic alkaline lixivium ; and then add 

 pure water to both folutions : and if there is a fair precipitation m 

 each, he may be allured that fome pus is prefent. If in neither a 

 precipitation occurs, it is a certain teft, that the material is en- 

 tirely mucus. If the material cannot be made to diflblve in al- 

 kaline lixivium by time and trituration, we have alfo reafon to be- 

 lieve thai: it is pus." Experiments on Pus and Mucus. Cadeii. 

 London. 



Dr. Cappe, of York, in his inaugural treatife de Hed~tica, and 

 Dr. Ryan, of Dublin, in his EiTay on Confumotion, have repeat- 

 ed thefe experiments of Mr. Darwin with nearly fimilar refults. 



7. Phthijis putmonalis. In pulmonary confumption the fever 

 is generally fuppofed to be the confequeuce of the ftimulus of 

 abforbed matter circulating in the blcod-veiTels, and not (imply 

 of its ftimulus on their extremities in the furface of the ulcers ; 

 as mentioned in Clafs II. 1. 5. and Clafs II. 1. 3. 9- The ul- 

 cers are probably fometimes occafioned bv the putrid acrimony 

 of effufed blood remaining in the air-cells of the lungs after an 



h^emoptoe. 



