HARDWICKE'S SCIENCE-GOSSIP. 



!25 



30, B. syncyanum (Ehbg.), Schroter. 



Vibrio syncyanus, Ehbg. 



V. cyanogcmis, Fuchs. 

 Morphologically the same as the preceding. 

 Producing the "blue milk." 



The colouring matter is changed by potash or soda into a 

 peach-blossom red, while acids restore the original colour. 

 Ammonia, on the contrary, only slightly changes the blue 

 to violet. 



31. B. (vriiginosHtn, Schroter. 



In the so-called green or blue pus, which is at 

 tiiiies found in wounds, etc. 



Even in this case the actively moving fungus-cells 

 are themselves colourless ; they secrete the colouring 

 matter, which is verdigris-green, often passing into 

 blue, in the matter which surrounds them. 



The species are partly always motionless, partly spon- 

 taneously motile, passing however at times into a condition of 

 rest. The rod-like cell lengthens itself by intercalary growth 

 to about double its original length, and then breaks up by 

 a transverse division into two daughter cells, which often 

 separate from one another, often also remain united. Since the 

 products of repeated divisions are arranged end to end, there 

 arise filaments which are often bent in a zigzag fashion, often 

 also straight, apparently unjointed, but the joints may be 

 brought into view by the application of staining materials. 

 The development and germination of the spores in Bacillus 

 subiilis are as follows : — The greater portion of the contents 

 collects itself into one part of the rod, which often appears as 

 a swelling and is sharply marked oft" from the other empty part 

 of the cell. Afterwards this strongly refringent darkened body 

 (the spore) disarticulates itself Irom the sterile part of the 

 cell ; this latter perishes, leaving the perfect spore behind. 

 These spores possess the power of withstanding adverse 

 influences of different kinds without injury to their vitality. 

 They can remain a long time ia the earth, often not to proceed 

 in their development for years, but they can also germinate 

 forthwith. On germination the spore first loses its brilliancy 

 and swells up somewhat ; then the membrane of the spore is 

 torn in the middle. The inner part of the spore is protruded 

 through the fissure, and grows into a new rod-like cell, the base 



^ 



[ fig. 161. — Bacillus suliiilis ;after Cohn) with 

 spores. 



esi: 



^^,.^.c■f^■.t J'' cT. V 



Fig. 164. — Bacillus subtilis (after Dallinger) X 4000. 



Fig. 162.— Bacillus Ulna (after Cohn). 



Fig. 165. — Micrococcus boiiibyces, Uom. the gastric juice of 

 a living silkworm (after Cohn) ; b, M.fulvus (after Cohn). 



Fig. 163. — Bacillus ulna (after Dallinger) X 3000. 



VI. Bacillus, Cohn. Cells elongated cylindrical, 

 almost always combined in straight rod-like {not at 

 all or slightly constricted) rows or threads, increasing 

 by transverse division. They form a Zoogloea, but 

 often also occur in dense swarms, without the 

 secretion of gelatine. Keprodiiction by spores. 



The genus Bacillus is very near to Bacterium ; 

 Bacterium Lineola especially is very similar to single 

 Bacillus cells. But they can be distinguished by the 

 fact that in the longer Bacterium cells self-division 

 has already begun, while in equally long Bacillus 

 cells no trace of division can be perceived. 



of which is still enclosed within the rent membrane, which is 

 frequently not thrown off till long afterwards. The demarca- 

 tion of the different species is difficult in this case also. 



A. — Colourless Species. 



32. B. subtilis (Ehbg.), Cohn. 



Vibrio subtilis, Ehbg. (Infiisionsth., p. 80, 



No. 91 ; pi. 5, fig. 6). 



Cells cylindrical, about twice as long as broad, as 



much as 6 yu long, furnished with a flagellum at 



each end. Usually several united together in 



pseudo-filaments, which are likewise motile, flexile. 



