EPIDEMIC INFLUENZA 107 



developed by Doctor Noguchi, based on the early ex- 

 periments of Doctor Theobald Smith. The Smith- 

 Noguchi culture medium, which had proved successful 

 in the cultivation of certain highly parasitic microbes, 

 consists of dilute blood serum or tissue fluid with a 

 small fragment of fresh sterile tissue usually rabbit 

 kidney and is thus very different from the artificial 

 broths and jellies commonly employed in bacteriology. 

 Besides furnishing nutritive substances the tissue frag- 

 ment creates an environment favourable to those pe- 

 culiar "anaerobic" microorganisms which can live only 

 in the absence of air. The choice of this medium for 

 the cultivation of the active agent of the animal trans- 

 mission experiments proved to be a fortunate one. 



In November, 1918, certain extremely minute but 

 characteristic spindle-shaped bodies were observed in 

 strictly anaerobic cultures of the filtered nasal washings 

 of an influenza patient in the early hours of the disease. 

 In size they approached the limit of vision with the high- 

 est powers of the microscope so that the sparse growths 

 in the early cultures were identified with the greatest 

 difficulty. Soon, however, other cultures were ob- 

 tained, both from the filtered nasal washings of other 

 influenza patients and from the whole or filtered lung- 

 tissue specimens of rabbits which had been typically 

 affected by these secretions, as has been described. 



As these minute microorganisms were carried through 

 successive generations of culture, they became better 

 adapted to artificial cultivation and multiplied more 

 luxuriantly, so that the cultures could be used in animal 

 experiments with unequivocal results. These experi- 



