284 PHILOSOPHICAL TRANSACTIONS. [anNO \6QS. 



gives an account of some experiments which he made, after the example of 

 Mr. Boyle, upon the human blood; experiments wherein he extracted from 

 that vital fluid not only ati alkaline salt, but (what no chemists before him had 

 conceived to be possible) an acid salt also ; and by these experiments he, more- 

 over, thinks he has been able to determine the relative proportions of the con- 

 stituent parts of the blood. 



From 50lb. of blood exsiccated in a copper vessel, and afterwards calcined 

 for 24 hours in a potter's furnace, were obtained fiij 3vij of grey ashes, which 

 effervesced with acids, turned syrup of violets and other blue vegetable colours 

 green, and precipitated a solution of corrosive sublimate. These ashes being 

 lixiviated, yielded §j of a fixed salt (possessing all the alkaline properties just 

 mentioned) almost as white as snow. Of this purified salt 3vij 42grs. were 

 mixed with §iij of well dried bolar earth; the mixture being put into a retort 

 (with the receiver luted to it) and subjected to a strong heat, there was distilled 

 from it §ss. ISgrs. of a spirit, which in colour resembled spirit of sulphur, and 

 was sharper to the taste than distilled vinegar. This spirit effervesced strongly 

 with salt of tartar, with vol. salts, &c.; and it reddened syrup of violets, tinc- 

 ture of turnsole, &c. so that it was evidently of an acid nature.* The matter 

 which remained at the bottom of the retort after the extraction of this spirit, 

 being lixiviated, gave jij. 3lgrs. of a light grey fixed salt; which produced no 

 sensible effervescence with any acid except oil of vitriol, although it turned 

 syrup of violets green, and precipitated a solution of corrosive sublimate, &c. 



To satisfy himself that nothing extraneous was derived from the copper 

 vessel in which the blood, in this instance, was exsiccated, the author repeated 

 the experiment upon blood exsiccated in earthen vessels. The results were 

 the same. 



In order to ascertain the proportion of vol. salt in the phlegm of blood, Mr. 

 Vieussens made what he terms an artificial phlegm, by adding different quan- 

 tities of the vol. salt extracted from blood, to a given quantity of distilled 

 water; until, by comparing the changes produced upon syrup of violets, and a 

 solution of corrosive sublimate, by equal quantities of his artificial phlegm and 

 of the real phlegm of the blood, he arrived at what appeared to be the true 

 proportions. After a number of unsuccessful trials in this way, he at length 

 found that by adding Igr. and a quarter to 12 ounces of distilled water he ob- 

 tained a liipior, which in colour, taste, smell, and consistence resembled the 

 natural phlegm of blood, and which, in equal quantities, produced the same 

 phaenomena with the beforementioned chemical tests, as the natural phlegm ; 



* The acid thus obtained was probably the phosphoric acid. The prussic acid would be dissipated 

 and destroyed by the previous toirefaction of the blood in the open fire. 



