HISTORY OF 



her Iiut'band lay, Avho had some time before died of the ssaie 

 disease ; and whom she, poor creature, soon followed. But 

 what showed the peculiar malignity of the air, thus suffering 

 from animal putrefaction, was, that the contagious steams had 

 produced spots on the very wall of their wretched apartment : 

 and Mr Boyle's own study, which was contiguous to a pest- 

 house, was also spotted in the same frightful manner. Happily 

 for mankind this disorder, for more than a century, has not been 

 known in our island : and for this last age, has abated much oi 

 its Niolence, even in those countries where it is most common. 

 Diseases, like empires, have their revolutions ; and those which 

 for a while were the scourge of mankind, sink unheard of, to 

 give place to new ones, more dreadful, as being less understood. 



For this revolution in disorders, which has employed the spe • 

 culation of many, Mr Boyle accounts in the following manner : 

 " Since," says he, " there want not causes in the bowels of the 

 earth, to make considerable changes amongst the materials that 

 nature has plentifully treasured up in those magazines, and as 

 those noxious steams are abundantly supplied to the surface, it 

 may not seem improbable, that in this great variety some may 

 be found capable of affecting the human frame in a particular 

 manner, and thus of producing new diseases. The duration of 

 these may be greater or less, according to the lastingness of 

 those subterraneous causes that produced them. On which ac 

 count, it need be no wonder that some diseases have but a short 

 duration, and vanish not long after they appear ; whilst others 

 may continue longer, as having under ground more settled and 

 durable causes to maintain them." 



From the recital of this train of mischiefs produced by the 

 dir upon minerals, plants, animals, and man himself, a gloomy 

 mmd may be apt to dread this indulgent nurse of nature as a 

 cruel and inexorable stepmother : but it is far otherwise ; and, 

 although we are sometimes injured, yet almost all the comforts 

 and blessings of life spring from its propitious influence. It 

 would be needless to observe, that it is absolutely necessary for 

 the support of our lives ; for of this every moment's experience 

 assures us. But how it contributes to this support, is not so 

 readily comprehended. All allow it to be a friend, to whose 

 benefits we are constantly obliged ; and yet, to this hour, philo- 

 ?ophers are divided as to the nature of the obligation. The 



