IX 



Scheffler n ) made a further investigation ofRothber- 

 ger's results and employed a 0.3 0.5% glucose agar to 

 which he added 1 % cone, neutral red solution. In this 

 medium B. coli produced a decoloration and a well 

 marked fluorescence, which Scheffler regarded as of 

 great importance. He came to the conclusion that a true 

 B. coli gave a reliable reaction and therefore the method 

 could be used to distinguish this bacillus from B. Ty- 

 phosus in water and faeces etc. 



In accordance with Rothberger and Wolff he found 

 that the reaction could also be obtained with certain 

 putrefactive bacteria, so that it was not absolutely specific. 



Hunter 18 ) who for some time had applied the me- 

 thod to many different strains of B. coli and typhosus 

 says, that although the reaction constantly succeeds 

 with bouillon, the best results are obtained with a shake 

 or stab culture in glucose agar (0.3 to 2 % glucose). He 

 states that the fluorescence is but feebly developed in 

 bouillon, which is not in accordance with the results 

 obtained by us, as a well marked fluorescence was 

 frequently seen in the bouillon cultures. Hunter's final 

 conclusions may be briefly given as follows: 



'!) That B. coli communis possesses to a marked 

 degree the power of reducing neutral red, producing a 

 superb canary yellow fluorescent colour of the medium. 

 2) That the B. typhosus never possesses this power 

 of reduction. 3) That the common pathogenic micro- 

 organisms do not give this reaction. 4) That by means 

 of neutral red it is possible within from 12 to 24 hours 

 to diagnose with absolute accuracy the presence of B. 

 coli communis ; '; and he finally stales that as far as his 

 experience went: "it was possible to diagnose by means 

 of neutral red the true coli group from the typhoid 

 group of micro-organisms." 



