714 l-HILOSOPHICAL TRANSACTIONS. [aNNO 1790. 



the experiment was repeated in the following manner. A. portion of the cancer- 

 ous virus, diffused through distilled water, was introduced into a small proof; a 

 little vitriolic acid was added ; the vessel was filled with distilled water, and a 

 crooked tube, also filled with that fluid, was fixed to its neck. The extremity of 

 the tube being then introduced into the mouth of an inverted bottle containing 

 water, and the flame of a candle being applied to the bottom of the proof, a 

 quantity of air was expelled, which was received in the bottle. This air, when it 

 was first disengaged, rose in the form of white bubbles ; it had a very fetid smell, 

 similar to that of the cancerous matter ; and the water which was impregnated 

 with it occasioned a dark-brown precipitate in a solution of nitrated silver. The 

 crooked tube being separated from the proof, a very offensive white vapour, re- 

 sembling in its odour the air extricated during the experiment, arose from the 

 mixture, and continued to ascend for nearly half an hour. When to a portion 

 of this smoking liquor, previously filtered, a little concentrated nitrous acid was 

 added, the fetid smell was entirely destroyed, a slight effervescence took place, 

 and a flaky substance that floated through the mixture was disengaged. 



The foregoing experiments prove, in general, that the fetid odour of the matter 

 of cancer is increased by the vitriolic, but entirely destroyed by the concentrated 

 nitrous and dephlogisticated marine acids ; that the aerial fluid, which is dis- 

 engaged by the vitriolic acid, is soluble in water, and that the solution deposits a 

 reddish brown precipitate on the addition of nitrated silver. Whence it follows, 

 that the cancerous matter contains a principle which has many of the properties of 

 hepatic air, and which may perhaps not improperly be termed animal hepatic air. 

 It has also been shown, that the matter of cancer is impregnated with an alkali 

 which is in such a state as to change the colour of vegetable tinctures. Dr. C. 

 had very little doubt that this was the volatile alkali : for it is well known, that 

 putrid animal substances frequently abound with that salt ; but have never, he 

 believes, been found to contain a fixed alkali in a disengaged state. With a view 

 however, more decisively to determine this point, he tried the following experi- 

 ment. A quantity of cancerous matter, diffused through distilled water, was in- 

 troduced into a glass retort to which a receiver was adapted. The mixture was 

 slowly distilled by means of a sand heat ; and a small quantity of the liquor which 

 came over into the receiver being poured into an infusion of Brazil wood, in- 

 stantly imparted to it a deep red colour. Hence it clearly appears, that the alkali 

 contained in the cancerous matter was the volatile, because it was separated by 

 distillation with a heat which did not exceed that of boiling water. 



It seemed extremely probable, that the above-mentioned alkali was united to 

 the aerial fluid with which the matter of cancer is impregnated. Of the truth of 

 this fact he was persuaded by observing, that the smell of the cancerous matter 

 was greatly increased by the addition of the vitriolic acid : for he could scarcely 



