660 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1910. 



which by no means really occurs. Autopsies are held only in a small 

 proportion of cases, and therefore some uncertainty exists. Besides 

 this, in many regions, even in entire countries, there is, for Avell- 

 recognized reasons, a certain hesitation attached to pronouncing a 

 diagnosis of pulmonary consumption, and the disease is called in- 

 stead chronic catarrh of the lungs, or something similar. It is, there- 

 fore, not always admissible to compare with each other the death 

 rates of pulmonary consumption of different countries without fur- 

 ther examination, and it is to be supposed that many cases of strik- 

 ing differences may be explained by circumstances of this kind. 

 This source of error has, however, no essential influence when we con- 

 sider the increase or decrease of mortality in the same country or city. 



On the other hand, it may be said that pulmonary consumption 

 is a very satisfactory subject for statistical investigation, because 

 its characteristic symptoms make its diagnosis quite certain, even by 

 the lait}^, so that for many matters where absolute exactitude is not 

 required, data are available, even though not supported by medical 

 authority or by autopsies. 



If in an investigation of the epidemiology of tuberculosis we go 

 back to early data concerning mortality from consumption, we find 

 the disease mentioned in the oldest records. 



In the writings of Hippocrates a very characteristic description 

 of pulmonary consumption is given, and we may conclude from it 

 with certainty that the physicians of that time were quite familiar 

 with the symptoms of the disease. It is stated in several places that 

 numerous persons have been affected by it.^ We must therefore con- 

 clude that phthisis already at that time played a part similar to that 

 Avhich it assumes at the present day. 



We find the first numerical data, however, much later, and these 

 relate to Sweden, where they were collected by the clergy. 



From these we obtain the highest figures which mortality from 

 phthisis has hitherto reached (Table 1). About the middle of the 

 eighteenth century the mortality in Sweden was. for the country, 

 21.5 per 10,000 persons, and it rose very slowly to '27.7 about 1830. 



iFrom the writings of Hippocrates (Grimm's translation). On Epidemics, p. 16: 

 •' For consnmption alone, as the most important single disease among those prevailing 

 at that time, liilled many people '" ; p. 57 : " The greatest and most terrible disease, 

 and the one which was the most fatal, was pulmonary consumption." 



