77 



Material. 

 This may be divided into three sets : — 



(1) Pathological specimens, chiefly from lobar pneumonia, 

 investigated in conjunction with Dr. F. Griffith {see his report) 

 and supplied during the period from April 1920 to the end of 

 December 1921. The majority of the specimens were from 

 patients treated in various Poor Law Infirmaries in London : 

 my thanks are due, among others, especially to Drs. Baly and 

 Perdrau of Lambeth, Dr. Harkness of Bermondsey, Dr. Brander 

 of Hackney and Dr. Spurrell of Bow. Cases of influenzal 

 pneumonia in South Wales, Sheffield and Bristol were responsible 

 for a few specimens both in 1920 and 1921. 



(2) Swabs from the nasopharynx of normal persons obtained 

 during November 1918, November 1919 and November 1920. 

 For these I am indebted to Mr. West, F.R.C.S., late Aural Surgeon 

 to St. Bartholomew's Hospital, who was good enough to take 

 swabs from the nasopharynx of out-patients attending the Ear 

 and Throat Department, and to Dr. Baly, who allowed me to 

 swab out-patients attending Lambeth Infirmary. By the kind- 

 ness of the latter I was also able to swab patients suffering from 

 influenza in the wards during the epidemic of November 1918. 



(3) Specimens of sputum from acute cases of influenza in 

 the wards of Bermondsey Infirmary during the epidemic of 

 January 1922 and nasopharyngeal swabs from normal school 

 children in Westminster during the same month. 



Technique. 



I have employed almost exclusively for the isolation and 

 culture of influenza bacilli Fildes's pepsinised blood agar* which 

 has proved much more satisfactory and convenient than any 

 other. 



On this medium the influenza bacillus outgrows most of 

 the ordinary micro-organisms found in sputum. Its colonies 

 appear after 24 hours incubation at 37° C. as sharply rounded 

 flat discs of 1 to 4 m.m. in diameter, perfectly transparent and 

 with no internal structure or iridescence. The only other bacteria 

 which form colonies on this medium resembling these at all 

 closely are the meningococci; the latter, however, are distinctly 

 less transparent. 



In addition to the production of these highly characteristic 

 oolonies, the features used for identification have been simple 

 (1) the microscopical appearance of the bacilli as minute short 

 Gram-negative rods and (2) the fact that no growth takes place 

 on ordinary agar or other media free from blood pigment. 



I have made no special study of the other cultural characters, 

 but have noted that about two-thirds of my strains have produced 

 abundant indol in broth containing pepsinised haemoglobin, 



* British Journ. Experim. Pathol., I, p. 129. 1920. 



