ZOOLOGY AND BOTANY, MIOKOSCOPY, ETC. 689 



apparently bilamellar, smooth, colourless membrane. This process may 

 take place in different conditions of the organism, in that of coccus, 

 bacillus, vibrio, or spirillum, but most frequently in the bacillus-form. 

 Earely is more than one spore formed in a mother-cell, which does 

 not thereby lose its power of swarming. They escape by the gradual 

 absorption of the wall of the mother-cell. The spores germinate im- 

 mediately, by the contents bursting through the cell- wall at a definite 

 spot, and elongating into a bacillus, which escapes from the membrane 

 of the mother-cell. 



The production of the gelatinous or zoogloea-form of the Schizomy- 

 cetes depends on the accumulation of resting-cells, and on the tendency 

 of their cell-walls to gelatinize ; this may be accompanied, or not, by 

 division ; and may take place in all the various stages of develop- 

 ment. Occasionally the zoogloea-colonies swarm out, leaving nothing 

 but the jelly behind. 



A scientific classification of the Schizomycetes is at present im- 

 possible ; the forms that are better known Zopf divides provisionally 

 into the four following classes : — 1. Goccacece. Known only in the 

 coccus-form, and the leptothrix-form resulting from it. Genus, Leuco- 

 nostoc. 2. BacteriacecB. Four stages of development known — coccus, 

 bacterium, bacillus, and leptothrix, the latter with no distinction of 

 base and apex ; no spiral form. Genera, Bacterium, Clostridium. 3. 

 Leptotricliem. Known in the coccus, bacillus, leptothrix, and spiril- 

 lum-form, the leptothrix-form displaying distinction between base and 

 apex. Genera, Leptothrix, Beggiatoa, Crenothrix, PJiragmidiothrix. 

 4. Cladotrichece. Known in the coccus, bacillus, leptothrix, and 

 spirillum-form ; the leptothrix-form provided with spurious ramifica- 

 tions. Genus, Cladothrix. 



All the various forms are described in detail ; the following are 

 but little known : — 



Leuconostoc mesenterioides Cienk. Appears spontaneously in the 

 sap of turnips and in molasses, forming massive gelatinous lumps 

 with the appearance of frogs' spawn. The germinating spore first 

 produces a coccus-cell inclosed in jelly, which elongates into a bacte- 

 rium, and then divides into two and afterwards into a greater number 

 of cocci connected together into a chain, and surrounded by a gela- 

 tinous envelope. These break up into longer or shorter pieces. If 

 the supply of nutriment is defective, spores are formed within some 

 of the cells of the chain, causing them to swell up ; the membrane of 

 the spore coalescing with that of the mother-cell, and cuticularizing. 



Bacterium aceti Kiitz. Occurs in the coccus, bacterium, bacillus, 

 and leptothrix-form ; the bacilli and leptothrices often not cylindrical, 

 but irregularly swollen. Has the power of converting alcohol into 

 acetic acid. 



B. merismopodioides Zopf. Occurs in putrid slime, and is distin- 

 guished by the peculiarity of the coccus-form dividing in two directions 

 into a merismopodium-like colony. 



Clostridium hutyrieum Prazm. In putrid vegetables ; causing the 

 butyric fermentation. When the bacilli develope spores, they swell 

 up into a fusiform or ellipsoidal form. 



