INFLUENZA. 



times troubiefome for a confiderable time after the febrile 

 ftate of the diforder had ceafed ; and a great weaknefs often 

 rL-mained after the difeafe. ' 



The influenza, as above defcribed, maybe taken as an ex- 

 ample of the epidemic at nil times of its appearance ; but it 

 lias fometjmes afliimed a more violent and inflammatory type, 

 been mare frequently accompanied with fymptoins of pleu^ 

 rily and peripneumony, and therefore more frequently fatal, 

 and alio laid the foundation for more numerous cafes oF pul- 

 monary confumption, than in the inftance of 1782. Such 

 Mas the fact, in regard to the influenza of 1762 in particu- 

 lar; which, indeed, appeared to be far more fatal, both at 

 the time of its raging, and in its confequences, as feveral 

 perfons continued languilhing under the remains of it for one 

 or two years, and never recovered. 



The caufes of the influenza have been the fubjeft of much 

 difference of opinion ; and all that has been faid in refpeft 

 to them rather tends to prove the difficulty of obtaining a 

 fufficient number of unqueftionable facts to found a clear 

 opinion upon, than to fet the fubjeft at reft. Three differ- 

 ent views of the matter have been taken by different phyfi- 

 cians : i. Some attributed the difeafe folely to the Hate of 

 the weather ; i. e. they believed it to be a common catarrh, 

 occafioned by changes in the fenfible qualities of the atmo- 

 fphere, fuch as cold, moillure, &c. : 2. Others afcribed it to 

 a particular and fpecilic morbid principle, totally different 

 from and independent of the fennble qualities of the atmo- 

 fphere, but refident in and conveyed by the air: 3. While 

 the greatell number concurred in the opinion, tliat the infln- 

 enza was contagious, in the ordinary acceptation of the 

 word, /. e. was propagated only by the contad, or at leall 

 by the fufficiently near approach, of an infefted perfon. 

 The Jir/l opinion, however, that it originated in the fenfible 

 variations of the air, feems to be untenable: for not only 

 was there no peculiarity of the atmofpherical temperature, 

 moifture, Sec, which was common to the different periods 

 when the influenza prevailed, or wasobvioufly different from 

 that of other feafons, when it had not appeared ; but the 

 ienfible ilate of the air preceding -and accompanying 

 the fame epidemic was different in different places. Thus, 

 tliough in moft parts of England it had been uncominonly 

 cold and wet, yet in the other parts of the world, as in 

 Germany, wliere the diforder \\'as equally general, it had been 

 very dry. Again, it wak obferved in feveral places, that 

 great alterations happened in the weather during its preva- 

 lence, without any fenfible change in the fymptoms of the 

 diforder. 



The /-ron'/ opinion, that'the caufe of the difeafe, though 

 not connefted with the fenfible qualities of the atmofphere, 

 was vet refideat in it, and thus conveyed from place to place, 

 was Supported upon the following grounds : 111. That thofe 

 who were moft expofed to the air were generally the firft 

 perfoBS attacked : zdly. That many had the diforder with- 

 out having -had any communication with a difeafed perfon : 

 ^dly. That feveral cfcaped though furrounded by perfons ill 

 of the difiaA; : 4tiily. That (nme'zuhok families were feized 

 at once : and, fthly. That fomc perfons had the diforder a 

 week or a fortnight before it began to be taken notice of as 

 a general one. Without prefuming to decide -upon fo diffi- 

 cult and intrfcate a que'.ljon,. we may itate the following ob- 

 .jeftions to 'thefe argument?. 



The firft argument, that thofe who were moft expofed to 

 the air were generally the firfl perfons attacked, (which, by 

 the way, was altogether denied by many obfervers,) is furely 

 bv no means in favour of the opinion, tTiat the caufe of the 

 diforder redded in the atmofphere ; for if it had refided 

 there, what ftiouid have prevented tiofe who ftaid at home 



from being infefted ? fince the air which they breathed mulfc 

 ncceffarily have been the fame as that breathed by thofe who 

 went out. But if, on the other hand, a communication with 

 fomeinfeAed perfon was neceffary to produce the diftemper, 

 it is very clear that thofe who went out of doors, and mixed 

 with the world, were more likely to get it than thofe who did 

 not ftir from home. 



Before the fecond argument, namely, that many were at- 

 tacked v.itliout having had any communication «-ith a dif- 

 eafed perfon, can be allowed to liave any weight, it muft be 

 clearly pVoved, nof only that the perfons themfelves had not' 

 had fuch communication, but alfo, that no perfon, who had 

 b^ near them, had previonfly been where the diforder ex- 

 iile^ for it is pretty clearly eftabhfhed, with refpcft to 

 other aflive contagions, fuch as the fmall-pox, &c. that a' 

 perfon, who has already fuffered the difeafe, may never- , 

 thelefs convey the contagion from one place to another. 



From the third argument, that many efcaped tliough fur- 

 rounded by perfons affefled with the difeafe, no infcrenee of 

 any confequence to the prefent queftion can be drawn ; it^ 

 being certainly not lefs difficult to account for their efcape" 

 when furrounded by difeafed perfons, than when fuirounded 

 by the fame air, which had (according to the hypotliefis) 

 caufed the difeafe in thofe perfons. 



With refpeft to the fourth argument, that fome -whole fi- 

 mihes were feized at once, without having been expofed to in-' 

 feclion, it may be remarked that, when we confider what 

 has been faid in anfwer to the fecond argument, it will be 

 very difficult to prove that they were not expofed to it ; 

 and equally difficult to give any reafons v.hy, if the exciting 

 caufe of the diforder refided in the air, any whole family Ihould 

 have been affefted by that caufe, rather than an equal num- 

 ber of perfons in divers families ; but if we fuppofe the dif- 

 eafe to have been propagated by perforial infercourfe, it is 

 very eafy to conceive in what manner it may have been com-) 

 municatcd to fome whole families at the fame time. Aiid, 

 in anfwer to tlie laft argument, that fome perfons had the 

 diforder a week or a fortnight before any others were known 

 to have it, it may be fufficient to remark, that, admitting 

 thefe cafes to have been really influenza, the fuppofition, 

 that the caufe of it exiiled in the air, will not render it more 

 eafy to explain why thofe perfons only Ihould at that time 

 have been affcfefed by this caufe. 



Thefe confiderations tend to favour the third opinion 

 above-m.entioned, that the difeafe was propagated by con- 

 tagion, in- the common acceptation of the term, tliat is, by 

 perfonal communication with the difeafed ; but they are' 

 very far from being decifive of the queftion. Indeed, the 

 queftion of contagion, as connected with any particular epi-' 

 demic, in which there is no palpable matter produced, by 

 which the difeafe can be communicated, is always difficult, 

 and has been agitated even with regard to the plague itfeUV 

 (See Contagion- and Epidemic.) But it has been fatis- 

 fatlorily demonftrated, that the contagion of all malignant 

 and eruptive fevers cannot be conveyed through the air to 

 any diftance (even many feet) from its fource. If the con-' 

 tagion of the influenza, therefore, could be fufpended and 

 conveyed through the atmofpheric air, fo as to fpread the 

 difeafe far and wide, it would form an exception to the ge- 

 neral properties of known contagions. Several fafts, re- 

 corded during the epidemic of 1 782, militate ftrongly againil 

 fuch a fuppolition. It was remarked, for example, that the 

 difeafe was prevalent in one piace a week or two before it 

 appeared in another, only a few miles diftant from tiie firft. 

 Thus it fliewcd itfelf at Edinburgh on the 20th of May, and 

 foon raged very much, and was prevalent at Glafgow in the 

 firft week in June ; ytt it did not appear at Mufielburprh. a 



