174 ADDENDUM 



In using the haemolysis test fresh cultures must be used. 

 Jupille, for example, found that this property is a transient one 

 which depends upon the age of the cultures and is usually 

 lost in cultures five days old ; while M'Leod found that the 

 haemolytic property reached a maximum of activity within 17 

 hours and remained constant up to 48 hours, after which it 

 gradually disappeared. 



The extent of the haemolytic action cannot be used as a 

 basis of classification as it depends (as M'Leod shows) upon the 

 extent to which the medium favours the active and prolonged 

 multiplication of the streptococcus. 



Broadhurst (1915) found that haemolysis does not seem to 

 be correlated with the results in litmus milk, gelatine or with 

 any of the Gordon reactions. Like other workers she found that 

 samples from pathological sources yielded the greatest propor- 

 tion of haemolyzing strains. Such strains may occur in throat 

 samples and in those from the alimentary canal. A markedly 

 high percentage (32 per cent.) was found in 101 strains isolated 

 from the stomachs and intestines of eight dogs. 



2. Fermentation reactions.- Two procedures have been 

 used to determine the capacity of streptococci to produce acid 

 from sugars, alcohols and allied substances. The original 

 method introduced by Gordon and employed by most workers 

 in this country is to qualitatively record the production of acid 

 as shown by the action on litmus added to the culture medium. 

 This procedure is described on page 8. 



The alternative method as used by Winslow and Palmer is 

 quantitative, the amount of acid produced being estimated by 

 direct titration, using phenol-phthalein as the indicator. Some 

 of the results obtained by Winslow and Palmer with this method 

 are given on pages 8 and 9. 



A considerable number of investigations have been recently 

 carried out either by this new modification or by the original 

 procedure, and the results obtained are interesting and valuable 

 as a basis for further investigation, but it cannot be said that any 

 very decided and constant differences have been established. In 

 other words the fermentation reactions of any given streptococcus 



