THE GENUS GRANULOBACTER. 189 



or minutes at a temperature of 95-ioo C. Among the products 

 of the fermentations set up by individual species of this genus 

 are : carbon dioxide always and hydrogen generally, but methane 

 is never found." 



Granulobader butylicum is the species producing butyl alcohol. 

 It is presumably identical with Gruber's Bacillus amylobader /., 

 and is frequently met with in the flour of cereals. It is anaerobic, 

 and produces from maltose normal butyl alcohol, hydrogen, and 

 carbon dioxide, but no butyric acid ; diastase is formed concur- 

 rently, but not glucase. A spontaneous butyl-alcoholic fermenta- 

 tion can be set up by gradually adding to 100 c.c. of boiling 

 water as much coarsely ground, unsifted, fresh barley-meal (from 

 Hordeum distichum nudum) as will produce a thick gruel, and 

 then cooling down to about 35 C. so quickly that the final portion 

 of barley-meal will have been exposed to 100 C. for a few seconds 

 only. The mixture is kept at a temperature of 35-37 C. At 

 the expiration of twelve hours bubbles of gas will be perceptible, 

 and the presence of butyl alcohol will be manifest, by its odour, 

 after a further twenty-four hours. If the aforesaid temperature 

 be strictly maintained, almost pure Gramdobacter butylicuin will 

 develop in the liquid, and a pure culture can be obtained there- 

 from, unbopped malt-wort gelatin forming a suitable medium, and 

 one of the methods described in 114 being employed. In this 

 medium the fission fungus in question will develop into milk-white, 

 visco-mucinous, non-liquefactive colonies. The fermentations in- 

 duced therewith (e.g. in unhopped malt-wort of not more than 

 10 Sacch.), and which must be carried out in the absence of 

 air, progress in two stages : so long as any free oxygen remains 

 dissolved in the liquid, development will proceed but slowly, 

 only carbon dioxide and hydrogen (no butyl alcohol) being pro- 

 duced. When the liquid is finally purified, then not only can the 

 appearance of the alcohol be observed, but also an unusually 

 vigorous increase of the cells, which will be found to be so full of 

 granulose that a drop of the liquid will become stained quite blue- 

 black by iodine. The endospores, which soon make their ap- 

 pearance, attain, with a breadth of i /*, a length which may be as 

 much as 2 //. This species is very sensitive to butyric acid. 



A second species is Granulobacter saccharobutyricum, the true 

 butyric acid bacterium, generally so called, and presumably iden- 

 tical with the Bacillus butylicus examined by Fitz. It is more 

 widely distributed and of more frequent occurrence than the last 

 named species, with which it is associated on cereal grains and in 

 the green malt, groats,, and flour prepared therefrom. It is this 

 species, also, which occurs, and gives rise to damage, in badly 

 prepared distillery yeast-mash. Glucose and (but with greater 

 difficulty) maltose are decomposed by this species, butyl alcohol, 

 carbon dioxide, and hydrogen in variable proportions being pro- 

 duced, in addition to butyric acid. From a morphological point 



