DIPHTHERIA is the term applied since the time of Bre tonneau and Trousseau to a disease of the mucous membranes or skin, occurring epidemically and spreading by contagion, and characterized by the formation of a membranous deposit with general symptoms of specific toxlemia. Physicians had long been acquainted with the local manifestations of the disease, such as diphtheria of the pharynx, larynx, skin, etc., but the relationship between these different types of the dis ease was first recognized by Bretonneau and his pupils, Velpeau and Trousseau (1821-28).
The exciting cause of the scourge, a peculiar bacillus, was first dis covered in diphtheritic pseudomembrane by Blebs in the year 1883, while Loftier in 1884 was the first to obtain it in pure culture and to demonstrate its pathogenic action in the lower animals. Although these bacilli could be found in almost every case on the mucous membrane attacked by the diphtheria, and although Loftier succeeded in producing pseudomembranes similar to the diphtheritic deposits by rubbing ba cilli into the injured tracheal mucosa of rabbits, the etiologic importance of the bacilli would nevertheless have remained in doubt if Roux and Yersin had not been able to isolate the toxin produced by the Klebs Loffler bacillus and in experiments on lower animals to produce with it the main symptoms of diphtheria, especially the characteristic paraly ses. The discovery of the exciting cause of diphtheria was followed ten years later by the discovery and introduction of a specific treatment. for the disease, von Behring's serum therapy. Received at first with scep ticism, the use of diphtheria antitoxin has in a few years conquered the whole world. Diphtheria, however, still belongs in the class of dan gerous diseases, but physicians can now face its dangers with a certain superior calmness, based on a consciousness of a clear knowledge of practically all the variations of the disease and on the possession of a remedy with a sure action in the majority of cases.
is seen in all climates and seasons but is more prevalent in cold countries and the colder months. While in the earlier centuries it apparently always occurred in more or less sharply defined epidemics, by the middle of the Nineteenth Century it had be come pandemic, owing to the development of commerce with more rapid means of transportation, so that now the disease practically never dies out in large cities. In addition, the epidemics have. shown great varia
tions in intensity, in the course of a single year as well as over longer periods. In the preceding century the mortality from diphtheria. in Germany rose steadily until it reached its highest point of 122,000 deaths in 1SSCI (see Fig. 77 and "Century-curve of Mortality from Diphtheria in Hamburg," Heubner's Text book.) Since then it has fallen with an increasing rate of decline to about 45,000 fatal cases in 1900 (Fig. 7S). Marked differences were often shown by the differ ent cities, this variation in each locality being dependent upon the favorable or unfavorable character of the disease, which can change from year to year in any place. Figure 79 shows the diphtheria mor tality in Munich, the maximum being passed long before 1SSG. The chart giving the number of deaths does not show so decidedly the intro duction of the antitoxin as does the chart giving the percentage of the fatal cases (see Fig. SO, percentage of fatal cases in Gratz). The approximate pro portions of the favorable and severe forms of diphtheria for the last decade in German cities is given in Fig. Si.
The primary localization of the disease and its character, as well, have changed at different times. We now see the disease beginning almost always in the pharynx, and other initial points are rather rare. In the first half of the preceding century, however, primary diphtheria of the skin and larynx were frequently met with; the Saxony. physicians before 1S60 were acquainted only with croup and looked upon pharyngeal diphtheria as a great rarity. In former times also, adults were very much more frequently attacked by the disease than is the case to-day. Nowadays, diphtheria is seen, with few exceptions, only in children. The greatest morbidity and mortality occur between the ages of two and five years. The susceptibility of infants shows a great increase after the age of six months. From the school age to adult life the incidence of the disease and its mortality show a steady decline.