146 HiTYKir ACID FERMENTATION 



ill pn>duie a thick L'ruel, and then cooling down to about 35 C. >o quickly 



in of bai -ley-meal will have been i-xposed to JOOC. for a few 



kept at a temperature of 35~37 C C. At the 



expii ''irs bubble- nf -a.- will be pncrpt ihle, 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 puiv itrumilolmcter 

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

 from, unhopped malt-wort gelatin forming a suitable medium, and one of the 

 met i ibed in 1 14 being employed. In this medium the fission fungus 



in question will develop into milk-white, vi>co-mucinous QOD-Uquefactive colonies. 

 'ions induced therewith (e.'/. in unhopped malt-wort of not more 

 than 10 Saceh.), and which must be carried out in the absence of air, progress 

 in two stages J as any free oxygen remains dissolved in the liquid, deve- 



lopment will proceed but slowly, only carbon dioxide and hydrogen (no butyl 

 aleohol) being produced. When the liquid is finally purified, then not only can 

 ; ppearance 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 

 make their appearance, attain, with a breadth of i /*, a length which may 

 be as mueh as 2 p. This species is very sensitive to butyric acid. 



A second species is Grannlobacter saccharobtUyricum, the true butyric acid 

 rium, generally so called, and presumably identical with the Jlacilhis buly- 

 licus 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 

 -i-inash. Glucose and (but with greater difficulty) maltose are decomposed 

 by this species, butyl alcohol, carbon dioxide, and hydrogen in variable propor- 

 tions being produced, in addition to butyric acid. From a morphological point 

 of view, it is closely allied to the first-named species, but the spores are some- 

 what smaller; also, like the other, it does not liquefy gelatin. Probably identical 

 with, or at least very closely related to G. aaccharobutyricwm is an anaerobic 

 ferment (Bacillus ///^//r/Vv/s), isolated by S. Botkin (I.) from Berlin and Breslau 

 milk, and also frequently noticed by FLUGGE (11.) in market milk. 



f;riinn/ol'(ff'l'-r lactobvtyricum is probably identical with the organism causing 

 butyric acid fermentation in calcium lactate, described by Pa&teur. When culti- 

 vated in the absence of air, it grows in the form of plump, short clo.-tridia, which 

 stain violet-blue (not pure blue) with iodine and convert calcium lactate into 

 butyrate, hydrogen and carbon dioxide being liberated. The endospores are 

 smaller ami shorter than those of the first-named species. When kept in 

 presence of air, this organism converts calcium lactate into lar^e spheroidal 

 ' carbonate, and in this case takes the form of slender short rods, 

 inblin;: tho>e of AV//-/7///X xnhtUlu and staining yellow with iodine. From the 

 Tded by lleyerinck, that this species in a stale of pure culture dies out 

 inoculations, whether air be admitted or excluded, it may be 

 iimed tl in ne(d> for its prosperous development the svmbiotic 



iati'di of another, still undetermined, species of fission fungus. 



[fl frequently found on ceieal grains, and is pre- 

 sumably identical with Pra/.mow>kiW/, / W///////./Y/. This specie.> develops 

 HOI '-torily in an unrestricted supply of air, and then assumes the form 

 of : la. When the a : i;.tion is deficient, spore-bearing clostridia appear, 



fermentative action i> noticeable, a small quantity (traces) of butyl 



alcohol. \\ith carbon dioxide, beinir formed, but neither hydrogen nor 



butyric acid. The L>j>l<>th, /./' heipiently found in dental mucus, 



