608 PHILOSOPHICAL TRANSACTIONS, [aNNO 1722. 



half. This was more evident, when a strong image of the candle was suc- 

 cessively thrown on that half of the card, whose image was under examination. 

 When the paper was held in the middle between k and b, the black line on 

 each colour was visible, but indistinct. 



N. B. Care must be taken that the colours be deep, because having acci- 

 dentally rubbed off some of the blue, the whiteness of the card under it, made 

 its image fly out farther, almost as far as that of the red. 



Concerning the Inoculation of the Small Pox,* and the Mortality of that 

 Distemper in the natural Way, By Dr. Nettleton, Physician at Halifax, 

 N'^374, p. 209. 



Two propositions are advanced by the favourers of inoculation, concerning 

 which the public seems to require more full satisfaction : viz. " That the distemper 

 raised by inoculation is really the small pox ; and that it is much more mild and 

 favourable, and far less mortal, than the natural sort." 



The former of these is not so much disputed now, as it was at first, when 

 this method was introduced, nor can it be made a doubt of by any one, who 

 has seen those that have been inoculated, and has also been much conversant 

 in the natural small pox. There is usually no manner of difference to be ob- 

 served between the one sort and the other, when the number of pustules is 

 nearly the same; but in both there are almost infinite degrees of the distemper, 

 according to the difference of that number. All the variation that can be per- 

 ceived of the ingrafted small pox from the natural, is, that in the former the 

 pustules are commonly fewer in number, and all the rest of the symptoms are 

 in the same proportion more favourable. They exactly resemble what we call 

 the distinct sort : the symptoms before the eruption are the very same, and 

 when the pustules begin to rise, their appearance is the same, as well as their 

 periods of maturation and declension ; they are at first of the same florid, rosy 

 colour, and when fully ripe, of as fair a yellow. They commonly rise as round 

 and as large as the other, and when they are very numerous, the inflammation 

 and swelling of the face comes on at the usual time, and is followed by the 

 swelling of the hands and feet, and only once I observed a salivation, though 

 the pustules were distinct. In the natural small pox, when the pustules are 



* Although the vaccine inoculation, a discovery which constitutes a new aera in medicine, and which 

 it cannot be doubted will transmit the name of Jenner with undiminished lustre to future ages, 

 has now superseded the inoculation of the small pox ; yet this and the following papers are reprinted 

 entire, as they exhibit a valuable set of facts and arguments relative to a subject which will ever be 

 interesting in an historical ix)int of view, and may even be made to furnish data for comparative 

 illustrations of the superior advantages of the vaccine over the variolous inoculation. 



