32G I'HILOSOPHICAL TRANSACTIONS. - [aNNO J 7/8. 



private practice of an easy cure, are often very tedious, and apt to assume 

 anomalous symptoms. Healthy persons, admitted for the cure of recent 

 wounds and other accidents, soon become pale, lose their appetite, and are 

 generally discharged weak and emaciated, but soon recover by the benefit of 

 fresh air. In some hospitals the cure of a compound fracture is rarely seen ; in 

 private practice, and a pure air, such cases seldom fail. Such and many more 

 are the effects of bad air, which, though not virulent enough to cause a putrid 

 fever in its more malignant form, is yet sufficient to excite it to such a degree as 

 to undermine the constitutions of the patients, and render the disorders, for 

 which they were admitted, anomalous, tedious, and fatal. 



It has been demonstrated, that the effluvia of vegetables, even while per- 

 fectly sweet and fresh, are equally poisonous with those from animal substances. 

 The vegetables were separated from their parent plant, consequently not in a 

 growing or vegetating state. — Exp. 14. Being desirous of finding the effects of 

 effluvia from ripe fruit upon air, 6 ripe gooseberries sliced were inclosed l6 hours 

 in a phial with 8 ounces of common air: the air being then put to the test, was 

 found to be diminished from 62" to 40". Hence it appears that fresh fruit have, 

 in common with other vegetable matters, a great power in polluting the air, and 

 rendering it noxious. 



Exp. 15. To find whether any part of the pernicious effects of vegetables on 

 air in the 12th experiment might be owing to their odorous particles, the follow- 

 ing experiments were made. In each, the quantity of inclosed air was 8 ounces, 

 the time of standing together 1 6 hours. • 



. ; 10 grains of musk diminished it from .... 63 to 62 



"o r Camphor 63 . . &2 



C I AssafoEtida 6'2 . 62 



' "S < Saftron 62 . . 62 



la I Opium 6o . . 58 



^ LVoi. Sal. Ammoniac 60 . . 58 



Musk and camphire were selected as examples of essential oils ; the 1st of the 

 animal, the 2d of the vegetable class. The assafoetida as an instance of the 

 fetid odour ; opium of the narcotic. Saffron, from its mode of preparation, is 

 incapable of corruption while kept dry, and could give nothing but pure odour. 

 The volatile salt was an example of the volatile odour. Hence we find, that pure 

 odour has little if any effect, in polluting the air. 



It is hence demonstrable, that the filling of rooms with nosegays and bunches 

 of flowers is by no means a safe practice, especially in close rooms or sick 

 chambers ; their effluvia are of so noxious a nature as quickly to render the air 

 unfit for tlie purposes of respiration, and cannot fail of having bad effects on 

 sick and valetudinary people in particular. But it is also evident, that the oflorous 

 parts of vegetables, when separated by art from tlie putrescent, are by no means 



