548 ) Dr. E. W.:A. Walker. ~ [Feb. 18, 
| P wm Saccharose. 
June 14—17...:..... 1st passage Reaction 0 
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The negative reaction reappeared occasionally until the middle of July, 
after which the organism remained a strong saccharose fermenter until the 
end of the observation (Aucust 13). It was then tested through all the 
media, but showed no change in any of its other test reactions. 
Land V in Raffiinose. 
Begun June 14. | 
V became a raffinose fermenter on the fifth passage and so remained as 
long as it was kept under observation (several weeks). 
L refused to ferment raffinose, though grown continuously in this medium 
until October 7. It was then carried on anaérobically in the raffinose medium, 
and began to change the colour to red on the third passage. This reaction 
continued to be obtained in successive passages, though until October 27 the 
blue colour was found to return on admitting air. From October 27, the red 
colour produced anaérobically remained permanent even when air was 
admitted. But on continuing the cultures aérobically from November 10 
to December 5, the organism still refused to ferment the raffinose in the 
presence of oxygen. 
The change of colour to red produced anaérobically, which speedily changed 
back again to blue on admitting air, has frequently been met with in other 
instances, and appears to be quite common. Still more frequently the blue 
colour is simply discharged in the anaérobic cultures. In a large number of 
cases the blue colour rapidly returns on the admission of air, reappearing first at 
the surface of the medium and travelling slowly downwards to the foot of the 
tube. The medium will frequently be found to be still quite strongly alkaline 
in reaction. 
The change concerned in this discharge of colour must apparently be one 
involving some deoxidation process, as the result of which the litmus is 
converted into a leuco-body, but I am at present quite unable to throw 
any light upon the actual nature of the change. It is, however, important 
that it should not be mistaken for an anaérobic fermentation of the test 
carbohydrate. 
As Andrewes pointed out, such fermentation may often be obtained quite 
