270 ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 



much more severe, although, they came upon a population to some 

 extent protected. At the same time there can be no doubt that an 

 epidemic may occur in any climate and in any weather. The tropics 

 are not exempt. An instructive instance of the subtle diffusion of 

 influenza occurred in a village of Central Africa, which was attacked 

 immediately after the arrival of two natives from an infected place far 

 distant. But outdoor life and less constant communications prevent 

 the quick diffusion and wide prevalence which belong to civilized nations 

 in temperate climates. 



The manifest, at present the only practicable and yet difficult, meas- 

 ures for preventing these great and very destructive epidemics are: 

 Precautions against the introduction of the pest by travelers and by 

 articles sent from infected districts ; immediate compulsory notification, 

 without fee, of all cases occurring in a district to the medical officer of 

 the district and through him to the central board; isolation so far as 

 can be arranged of all the early cases in a district at the homes of the 

 patients; prohibition of attendance of infected persons at any assem- 

 blage; and publication of the importance of ventilation, and of living, 

 warmly clothed, as much as possible in the open air, unless actually 

 stricken. During the period of illness, and for some time after recov- 

 ery, the greatest care is required to avoid chill, which often induces 

 pneumonia or other evils. The fresh outer air can only be safely 

 breathed when the symptoms have subsided and when the strength has 

 partially returned. It is remarkable that cold air alone, however pure, 

 seems capable of causing a relapse when the system has been greatly 

 enfeebled and the breathing organs left in a highly sensitive condition. 



COLDS. 



Colds and sore throat have never received the attention they deserve 

 from an etiological point of view, owing probably to the slight character 

 of the majority of cases. Yet they are important, first for their wide 

 diffusion, endemicity, and frequency, and secondly for their effect in 

 giving opportunity 'for the attack of more serious disorders, among 

 which may be mentioned diphtheria, measles, pneumonia, bronchitis, 

 and consumption. Close observation for many years has led the pres- 

 ent writer to the conclusion that though primarily a chill, that is 

 exposure, insufficiently clad, to a draft or cold air, is very frequently 

 sufficient to give a slight cold or sore throat, or the feeling of one, yet 

 severe colds are caught in general either (1) in marshy or low and damp 

 situations, or in conditions somewhat similar to those which produce 

 malaria; or (2) by infection from persons after the manner of other 

 infectious diseases. It would appear as if the microorganism, or one 

 species of microorganisms, which sets up a sore throat and severe cold, 

 inhabits the upper layer of earth, especially in damp or marshy places, 

 where decaying vegetable matter abounds, and passes into the air, 

 especially in summer and autumn evenings when the earth and water 



