176 BACILLUS SUBTILIS AND ITS CONGENERS. 



changing into a sticky mass, capable of being drawn out into long 

 threads, and having a repulsive sour-sweet smell. EMIL LAURENT 

 (II.) was the first to examine this disease closely, and he attributed 

 it to a fission fungus, which presumably also plays a part in the 

 normal fermentation of dough (dealt with in the second volume), 

 and has therefore received the name of Bacillus panijicans. This 

 is undoubtedly a species of the group of potato bacilli. A second 

 case of this disease was investigated by KRATSCHMER and NIEMI- 

 LOWICZ (I.) by the aid of the plate culture method, whereby B. in. 

 vulfjatus was recognised as the exciting agent. According to the 

 researches of Aime Girard, reported by BALLAND and MASSON (I.), 

 the temperature prevailing in the interior of loaves of bread during 

 the baking process ranges between 100 and 102 C. The duration 

 of exposure to this temperature being insufficient to kill the spores 

 of potato bacilli, those originally present in the flour will still be 

 found alive in the finished loaf. The sites occupied by these 

 organisms, which germinate and reproduce immediately, will then 

 become the headquarters of active masses of microbes, as already 

 described. Batches of bread containing much bran are especially 

 liable to this disease, since it is on this part of the grain, and not 

 on the enclosed flour, that the bacteria reside ; and, as a matter of 

 fact, it is commissariat (military) bread and Graham bread that 

 are most frequently affected, as was pointed out both by Loeffler 

 and UFFELMANN (I.). The latter observer found the Bacillus 

 mesentericus vulgatus to be associated in this disease with a second 

 allied species, viz., the Bacillus liodermos, discovered in cows' milk 

 by LOEFFLER (III.), which owes its other name of "gum bacillus" 

 to the thick gummy appearance of its zooglosa-like cultures on cut 

 potatoes. That the bread disease in question does not make its 

 appearance so frequently as might be expected from the (often very 

 large) number of potato bacilli found in the flour is due to the 

 strongly acid reaction of the dough, which facilitates the extinction 

 of the germs. 



111. Bacillus Fitzianus. 



If a cold-prepared infusion of hay be left to stand at room 

 temperature, there quickly forms on the surface of the liquid a 

 skin composed of various organisms, including the bacillus named 

 above, the chemical activity of which was first examined by 

 A. FITZ (III.). If a little of this skin be transferred to a sterilised 

 solution of 2 per cent, of meat extract and 5 per cent, of 

 glycerin that has received an addition of some 10 per cent, 

 of calcium carbonate, then the said microbe develops and acts on 

 the glycerin (C 3 H 8 O 3 ) in such a manner that ethyl alcohol and 

 volatile acids are the chief products formed. Fitz obtained, in 

 two experiments, a yield of alcohol amounting to 25.7 and 25.8 

 per cent, respectively. The fermentation is very brisk, and attains 

 its maximum within twenty-four hours. 



