INFLUENZA 93 



to media containing haemoglobin. The influenza bacillus seems to 

 grow better on slants freshly streaked with blood than on those which 

 have been made for some time, and they appear to grow better on this 

 surface smear of blood than on a mixture of agar and blood. 



The influenza bacilli are most likely to be isolated from the sputum of broncho- 

 pneumonia due to this organism. It has also frequently been found in the nasal 

 secretions of influenza patients. Exceptionally, it is present in the blood, and has 

 been isolated in cases of meningitis from cerebrospinal fluid. It also occurs at times 

 in anginas, but then usually associated with other organisms. Infection probably 

 only takes place by contact. It is a very small bacillus which in sputum tends to 

 show itself in aggregations, especially centering about M. tetragenus. It stains 

 rather faintly when compared with cocci, so that a smear of sputum stained with 

 formol fuchsin shows a deep violet staining for the M. tetragenus or other cocci, 

 and scattered around in a clump-like aggregation we see these minute, rather faintly 

 stained rods. They also tend to stain more deeply at either end, so that they some- 

 times appear as diplococci. Gram's method, counterstaining with formol fuchsin. 

 is excellent for their demonstration. The red bacilli and the violet-black cocci are 

 easily distinguished. 



To cultivate them, rub the sputum, or at autopsy the material from 

 a lung, on a slant smeared with human blood (pigeon's blood is also 

 satisfactory), and then without sterilizing the loop, inoculate a second 

 blood slant; then a third, and possibly a fourth. The colonies appear as 

 very minute dewdrop-like points which seem to run into each other in a 

 wave-like way. To test such colonies we should transfer a single colony 

 to plain agar and blood-serum, trying not to carry over any blood. If 

 the least trace of blood is carried over, they may grow on agar or blood- 

 serum. Organisms resembling the influenza bacillus have been isolated 

 from whooping-cough. Such organisms have also been found in the 

 fauces of well persons. In many epidemics of influenza the bacillus 

 has not been isolated, or success has obtained in only a small proportion 

 of the cases. Etiological factors in conditions more or less resembling 

 influenza may be the Streptococcus, Pneumococcus, or M. catarrhalis. 

 The influenza bacillus seems to grow best in symbiosis with some other 

 organism, especially with S. pyogenes aureus. 



Koch -Weeks Bacillus (Koch, 1883). This produces a severe 

 conjunctivitis. It is very common in Egypt and is also a frequent cause 

 of conjunctivitis in the Philippines and in temperate climates. 



Smears made from conjunctival secretion show large numbers of 

 small Gram-negative bacilli, especially contained within pus cells, but 

 also lying free. They are more difficult to cultivate than the influenza 

 bacillus, but the same general methods hold. The vitality of this 



