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THOMPSON YATES LABORATORIES REPORT 
maltose and free sulphur were added to the medium, but not otherwise. Hence they 
looked upon the formation of sulphide as an accident of fermentation. 
On the other hand, Beijerinck 1 found that members of his ' aerobacter ' group, 
which liberated free hydrogen as a result of fermentation, did not form hydrogen 
sulphide thereby when flowers of sulphur was added. 
It was ascertained that at least a number of the organisms fermenting glucose 
form hydrogen gas in this process. The test used was the simple qualitative one of 
exploding with oxygen. The gas was obtained in the following manner : — Flasks of 
150 to 200 c.cm. capacity were provided with closely fitting rubber corks, perforated 
for the passage of the shorter limb of U shaped tubes. These were sterilized and 
filled with sterile two per cent, peptone, containing one-half per cent, glucose. After 
inoculation the flasks of medium were incubated in an inverted position, the long 
limb of the U tubes extending to the full height of the flasks, and communicating by 
rubber tubing with another vessel, which received the fluid displaced by the gas formed. 
In this way from 20 to 75 c.cm. of gas were obtained from the various flasks, accord- 
ing to the fermenting power of the respective organisms. 
The gas thus formed was collected in test tubes under water, and thoroughly 
washed in lime water, to get rid of the carbon dioxide present, which was formed in 
greater or less amount in every instance. Air was then admitted to the extent of 
about two and a halt volumes of the remaining gas, and a flame applied to the mouth 
of the tube. The sharp, high pitched report of hydrogen was obtained with an almost 
colourless flame in the instance of organisms Nos. 3, 5, 7, 12, 13, 14. In the other 
instances, a low pitched report or strong puff resulted ; the original gas burning down 
the tube with a blue flame. Of course hydrogen may have been present in these cases 
also in small amount; so also may marsh gas. 
It has been already stated that glucose favoured the formation of hydrogen 
sulphide with many of the organisms. In no instance did it appear retarding in its 
influence. Now if nascent hydrogen, acting on flowers of sulphur, forms hydrogen 
sulphide, it is most probable that at least a certain amount of the increase resulting 
from the addition of glucose is attributable to the hydrogen evolved. 
Sodium amalgam in distilled water, in which sulphur is suspended, gives rise to 
an excessive amount of hydrogen sulphide in a few hours at 37 0 C. The strength of 
the alkali formed at the end of the reaction was slightly above that of normal solution. 
A potassium hydrate solution of this strength effects no change in the sulphur unless 
heated, when it readily dissolves it. 
But glucose favoured the formation of hydrogen sulphide by organisms also, 
which form no gas whatever from this sugar, viz., Nos. 1, 6, and 9. It would seem 
then that the chemical action occurring as a result of the addition of glucose, is favour- 
able to the formation of hydrogen sulphide, apart from the evolution of hydrogen. 
