INFLUENZA. 369 



rapidity of its spread would seem to negative the idea of there being any connection 

 between human intercourse and the propagation of the disease. We are told that 

 at St. Petersburg, in 1782, 40,000 people were attacked with influenza in a single 

 night, and this clearly could not have been by contagion. Moreover, the epidemics 

 do not seem to follow the great lines of commerce. On the other hand, when it has 

 entered a town in which investigations can be carried on, it has frequently been 

 proved that the first cases have been introduced, and that the townspeople nearest 

 the invalids have been the first to suffer. So also when it breaks out in a house, it 

 often attacks one person after another. In some instances isolation or seclusion of 

 a community, as in prisons, has given immunity ; or, at all events, the inmates have 

 not been attacked. All contagious diseases have a remarkable property, and that is, 

 that after the entrance of the poison into the system, there is a period of incubation 

 or latency during which it lies dormant and produces no symptoms, or, at all events, 

 none of which we are cognisant. This incubative period is supposed not to exist 

 in the case of influenza, which strikes down persons in perfect health almost like a 

 stroke of lightning. In some cases, however, a period of incubation may possibly 

 have existed, but even then it is undoubtedly very short. Whether influenza affords 

 immunity from future attacks is another point on which there is some discrepancy 

 of opinion. Although persons seldom suffer twice during the same outbreak, it ?s 

 probable that they are not protected against a subsequent epidemic. 



Influenza occurs both in men and in women, and with about equal frequency. 

 It attacks people of all ages ; but young children, it is said, are less affected by it 

 than old. Domestic animals dogs, cats, &c. often suffer in the same way. In 

 1827 there was an epidemic of influenza amongst horses, which spread over almost 

 the whole of Europe. At that time influenza prevailed among men in North 

 America, Mexico, and Siberia, but not in Europe. Persons in over-crowded 

 dwellings usually suffer more than those who are more favourably situated as 

 regards sanitary conditions. In several instances large schools and barracks have 

 been first attacked, the disease raging there for some days before breaking out in 

 the town around. People living in low, damp, ill-ventilated places are more likely 

 to suffer than others. 



The symptoms of influenza are somewhat as follows : The patient feels chilly, 

 or perhaps shivers ; presently headache occurs, with a sense of tightness across the 

 forehead ; the eyes become tender and watery ; and sneezing and a copious acrid 

 discharge from the nose ensue, followed or accompanied by heat and uneasiness 

 about the throat, hoarseness, a troublesome cough, a sense of constriction in the 

 chest, and oppression of breathing. In fact, the symptoms are those of a very bad 

 cold, to which are added a sudden early and extraordinary subdual of the strength, 

 and most commonly great depression of spirits. The debility which comes on at the 

 very onset of the complaint is one of its most striking phenomena, occurring as it 

 does almost instantly, and being apparently so much greater than would have been 

 anticipated from the symptoms it ushers in. Indeed, this rapid and remarkable 

 prostration is more essentially a part of the disorder than the catarrhal affection, 

 which is sometimes, though rarely, absent or imperceptible. Not unfrequently there 

 are disturbances of the digestive organs , the tongue is white and creamy, appetite 

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