The high incidence, namely, 84.1 per cent, of B. influenzæ in the bronchi is particularly noteworthy; it exceeds that of pneumococci, the well-recognized cause of lobar pneumonia, within the lung. It is found much less frequently within consolidated lung tissue and shows no tendency to invade the heart’s blood. B. influenzæ finds the most favorable conditions for its multiplication within the bronchi.
In view of the frequent occurrence of coexisting lobar and bronchopneumonia it has appeared desirable to determine how far the existence of obvious bronchopneumonia modifies the bacteriology of lobar pneumonia. In Table XXXI the incidence of pneumococci, hemolytic streptococci, staphylococci and B. influenzæ after death with lobar pneumonia on the one hand is compared with their incidence after combined lobar and bronchopneumonia on the other.
Pneumococci are found in the lung more frequently with lobar than with combined lobar and bronchopneumonia. The incidence of hemolytic streptococci and of staphylococci in the lung is on the contrary higher when bronchopneumonia is associated with lobar pneumonia. It is not improbable that these microorganisms have a part in the production of associated bronchopneumonia. The frequency with which microorganisms invade the blood is almost identical in the two groups.
| Table XXXI | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| With Lobar Pneumonia Alone | |||||||||
| NO. OF CULTURES | PNEUMOCOCCI | HEMOLYTIC STREPTOCOCCI | STAPHYLOCOCCI | B. INFLUENZÆ | |||||
| NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | ||
| Bronchus | 30 | 20 | 66.6 | 9 | 30 | 15 | 50 | 26 | 86.7 |
| Lung | 34 | 29 | 85.2 | 7 | 20.6 | 3 | 8.8 | 18 | 52.9 |
| Blood | 54 | 36 | 66.7 | 7 | 13 | ||||
| With Combined Lobar and Bronchopneumonia | |||||||||
| NO. OF CULTURES | PNEUMOCOCCI | HEMOLYTIC STREPTOCOCCI | STAPHYLOCOCCI | B. INFLUENZÆ | |||||
| NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | ||
| Bronchus | 14 | 9 | 64.3 | 5 | 34.3 | 7 | 50 | 11 | 78.6 |
| Lung | 19 | 12 | 63.2 | 6 | 31.6 | 5 | 26.3 | 8 | 42.1 |
| Blood | 33 | 21 | 63.1 | 4 | 12.1 | ||||
The relative frequency with which different types of pneumococci produce lobar pneumonia under the conditions existing when Camp Pike was attacked by an epidemic of influenza is indicated by Table XXXII in which instances of lobar pneumonia alone and of combined lobar and bronchopneumonia are listed separately.
Pneumococcus I and II, which are found approximately in two-thirds of instances of lobar pneumonia occurring in cities, have an insignificant part in the production of these lesions. Pneumococcus IV and atypical Pneumococcus II, which are commonly found in the mouth, are the predominant cause of these lesions, and with Pneumococcus III, also an inhabitant of the mouths of normal individuals, have been the cause of two-thirds of all instances of lobar pneumonia observed in this camp.
| Table XXXII | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| With Lobar Pneumonia | |||||||||||
| NO. OF CULTURES | PNEUMOCOCCUS I | PNEUMOCOCCUS II | PNEUMOCOCCUS II (Atyp.) | PNEUMOCOCCUS III | PNEUMOCOCCUS IV | ||||||
| NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | ||
| Bronchus | 30 | 1 | 3.3 | 1 | 3.3 | 4 | 13.3 | 4 | 13.3 | 10 | 33.3 |
| Lung | 34 | 1 | 2.9 | 2 | 5.9 | 9 | 26.5 | 6 | 17.6 | 11 | 32.4 |
| Blood | 54 | 2 | 3.7 | 2 | 3.7 | 12 | 22.2 | 3 | 5.6 | 17 | 31.5 |
| With Combined Lobar and Bronchopneumonia | |||||||||||
| NO. OF CULTURES | PNEUMOCOCCUS I | PNEUMOCOCCUS II | PNEUMOCOCCUS II (Atyp.) | PNEUMOCOCCUS III | PNEUMOCOCCUS IV | ||||||
| NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | ||
| Bronchus | 14 | 2 | 14.3 | 1 | 7.1 | 3 | 21.4 | 3 | 21.4 | ||
| Lung | 19 | 1 | 5.3 | 5 | 26.3 | 6 | 31.6 | ||||
| Blood | 33 | 2 | 6.1 | 3 | 9.1 | 4 | 12.1 | 12 | 36.4 | ||
There is no noteworthy difference in the occurrence of these types of pneumococci among instances of lobar pneumonia, on the one hand, and of combined lobar and bronchopneumonia, on the other. Different types exhibit no noteworthy differences in their ability to penetrate into lungs and blood.
Hemolytic Streptococcus with Lobar Pneumonia.—There can be no doubt that the concurrent infection with microorganisms other than pneumococcus modifies the progress of lobar pneumonia. With lobar pneumonia alone hemolytic streptococci have entered the bronchi in 30 per cent of instances and have penetrated into the lungs in 20.6 per cent; with associated lobar and bronchopneumonia the same microorganism has entered the bronchi in 34.3 per cent of instances and invaded the lung in 31.6 per cent. Hemolytic streptococci are the only microorganisms other than pneumococci which, in association with lobar pneumonia, have found their way from the lungs to the blood stream; more than one-third of all instances of lobar pneumonia in which hemolytic streptococci find entrance into the bronchi die with streptococcus septicemia.
Separation of instances of lobar pneumonia into groups on the basis of the occurrence of red or gray hepatization shows that infection with hemolytic streptococcus is more likely to occur during the early stages of the disease. The average duration of lobar pneumonia with red hepatization has been 3.7 days, with red and gray hepatization, 5.1 days, and with gray hepatization, 7.5 days. Infection with hemolytic streptococcus has occurred in association with red or gray hepatization as shown in Table XXXIII.