SMALL-POX. 



complete expofure to the contagion, inoculation has been 

 immediately performed from a confluent fubjedl ; yet the 

 fubfequeiit difeafe has been diftinft and mild. We re- 

 member to have heard Dr. Gregory, the able profeflbr of 

 the praftice of phyfic at Edinburgh, alTert, in his ledlures, 

 that he had once taken matter from the confluent fmall- 

 pox of a dying child, with which he inoculated two of its 

 brothers : they had both a very mild difeafe : one of them, 

 however, had previoufly taken the cafual infeftion, for he 

 iickened in three days from the time of inoculation. In- 

 deed we could (late other faCls, from the fame authority, 

 to prove that matter, taken from the puHules of the dead 

 body, has produced even the mildelt form of fmall-pox. 

 It is manifelt, therefore, nutwithftanding the prejudices of 

 mankind, that the nature of the original contagion has no 

 influence in modifying the difeafe which it inflidls : and 

 we muit infer, th.it the various forms which tlie difeafe 

 allun.es, origmate from fome particular ftate of the confti- 

 tution in the mdividnals whom it thus varioufly handles. 

 And this condition of the conltitution mult be the refult of 

 external caufes, fuch as the feafons, and ftate of the atmo- 

 fphere ; or of internal and perfonal caufes, fuch as plethora, 

 obefity, irritability, or the contrary, depending on original 

 conformation, or upon indulgence, intemperance, affections 

 of the mind, and lo forth. It is not the contagion of fmall- 

 pox alone, which is varioufly modified in this way by the 

 cxilling condition of tiie conftitution ; almolt all external 

 agents are fo modified. The fcratch of a thorn will not 

 be felt for an hour by one perfon ; while in another it will 

 inflame and form an abfcefs, even excite the abforbents, 

 and produce a bubo and fever ; or it may run on to gan- 

 grene, and occafion death. In like manner, if feveral people 

 are expofed to cold, by falling into water, for inltance, and 

 remaining wet : the effefts will be very different individually. 

 Many will cfcape without inconvenience ; fome with a 

 common coryza or fore-throat ; another will be confined to 

 bed for weeks with an univcrfal rheumatilm ; another will 

 be attacked with pleurify, or a fpitting of blood, or an 

 inflammation in the bowels. It is preciiely the fame with 

 the varieties of fmall-pox : they are not the refult of a 

 difference in the caufe, but folely of a difference in the 

 Itate of individual conftitutions. 



Tlie cffeft of different fcafons upon the human conlli- 

 tution does not admit of very fatisfadtory explanation. 

 Sydenham and Boerhaave, both able obfervcrs of nature, 

 rtmarkcd, that the regular and dillinft fmall-pox ufually 

 appears about the vernal equinox, when it is epidemic, 

 increafing through the fummer, and attaining its height 

 and fcverity in the autumn, and commonly difappearing 

 with the approach of the winter's cold. They both alfo 

 obftrved, that if it commences early, as in January or 

 February, (and Boerhaave adds, more particularly if it has 

 been abfent from the place fix years,) the following fummer 

 will be dillinguiflied by an epidemic of a fevere and fatal 

 kind, fparing none who have not prcvioufly undergone the 

 difeafe, and proving extenfively dcltruftive. 



The internal peculiarities of conltitution, which mo- 

 dify the operation of morbific caufes in general, and of 

 the contagion of fmall-pox in particular, are more obvious 

 and intelligible. Various hypothefes about the fermentation 

 excited in the blood, and the free exit or depofition in the 

 Ikin of the contagious matcer, thus multiplied by that 

 proccfs, have been formed to explain this point : and even 

 Dr. CiiHcn has adopted this ablurd humoral notion, and 

 endeavours to point out the circumftances " which deter- 

 mine more or lels of the variolous matter to Jl'tck in the Jim, 

 or to pals freely through it." (Firlt Lines, <i 598.) But 

 Vol.. XXXIII. 



thefe notions are inconfillent with fafts. In the firft place, 

 there is no evidence that the contagion afts like leaven 

 upon the blood, " and affimilates a great part of it to its 

 own nature." (CuUen, loc. cit.) The blood, as far as 

 its properties are cognizable by the fenfes, pcffefles no 

 qualities which are not common to all inflammatory difeafes. 

 There does not appear, indeed, to be any thing analogous 

 to fermentation in the procefs. The pus that is generated 

 is the refult of the inflammatory aftion of the veffels of the 

 llvin, and is generated in the fliin only ; it is not floating in 

 the mafs of circulating fluids, and detained in the fliin, as 

 by a fieve. Whatever, therefore, increafes the inflamma- 

 tory aftion, increafes the number of puflules. Thus, parts 

 of the body that are much heated, as by lying upon them, 

 or keeping them in long and clofe contaA, have 3 greater 

 number of puftules than others ; and parts that are covered 

 with plalters, cfpecially thofe of a ftimulant kind, are 

 always more thickly befet with pultules. If we extend this 

 principle to the conftitution generally, we fliall find, that 

 thofe perfons who are by nature, their period of life, their 

 mode of living, previous indifpofition, the feafon of the 

 year, or other caufes of a more irritable and inflammatory 

 habit, will be more liable to fuffer fevcrely from the in- 

 fluence of fmall-pox. An intelligent writer has ftated, 

 from his own obfervation, that perfons of a fwarthy com- 

 plexion, of a dry rigid fibre, not much difpofed to per- 

 fpire, with brown or black hair, which is of a ftrong texture 

 and in great quantity, are more liable to a fevere fmall-pox 

 than thofe of a fair complexion, with thin, weak, and light 

 hair, and who are moderately fat, but perfpire freely. He 

 remarks, too, that '• perfons afflifted with the palfy, ague, 

 dropfy, and rickets, have commonly a favourable fmall-pox ; 

 and thofe afflicted with the two former frequently recover 

 from both." (Roe on the Small-Pox, p. 57.) But the 

 natural irritability may be much augmented or diminifhed 

 by various circumftances, and thus the danger from the 

 attack of fmall-pox in like manner increafed or leffened. 

 Thus, to ufe the words of the fame author, " if a perfon 

 fliould live intemperately, ufe violent excrcife, drink much 

 fpirituous liquors, or give any occafion whatfoever to inflam- 

 mation, before the attack of the fmall-pox, the difeafe will 

 prove more virulent, although tlie natural habit be good. 

 On the contrary, if a perfon be of an indifferent habit, and 

 an unpromifing temperament, but live temperately, eat 

 little animal food, and lead a fober and fcdentary life, be- 

 fore the difeafe attacks him, he bids fair for a happy reco- 

 very." We may add, that, upon the fame principle, the 

 adult age, as more robull and more connedted with full 

 living, is more liable to fuffer the difeafe fevcrely than child- 

 hood. 



It feems, therefore, fatisfaftorily proved, " that an in- 

 flammatory ftate of the whole fyftem, and more particularly 

 of the flcin," is the caufe of the multiplication of the puf- 

 tules, as well as of the other circumftances, which belong 

 to the confluent fmall-pox, fuch as the early eruption, the 

 erythematous rafli, the continuance of the fever, the cffu- 

 fion of a more ichorous matter, and from thence the pecu- 

 liar form, hue, incruftation, &c. of the puftules. See 

 CuUen, Firft Lines, ^ 600. 



Diflcrent caules have been affigncd for the fuperior mild- 

 iiels of the difeafe, when produced l)y inoculation, over that 

 which occurs in the cafual way. Some have fuppofed that 

 this advantage arofe from having the choice of the matter 

 of infeftion in the former cafe ; and others have imagined 

 that it was owing to the fmall quantity of matter which 

 was introduced by the lancet. But from what has been 

 faid above, it is inanifell that the choice of the matter i* of 

 Y no 



