276 SUMMARY OF CURRENT RESEARCHES RELATING TO 



stage. In this, at a given moment, elements of all sizes and forms arc 

 to be seen, some like Leptofhrix, Bacillus, or Bacterium, others like 

 Vibrio, and others like Spirillum ; their principal character is their 

 mobility, and they continuo to segment very actively ; when the 

 segmentation comes to an end, thcro are a number of short Bacterium-like 

 forms of great activity. The dissociated state is in direct relation with 

 tho activity of tho phenomena of putrefaction. In the third stage the 

 filaments interlace with ono another, and extend over tho surface of the 

 culture-liquid ; from this tho zooglceic stago is most often derived, 

 though tho latter may occur if a stop is put to the putrefactive activity. 

 Tho zooglceic patches are characterized by their distinctly stellate form, 

 a modo of arrangement which has not hitherto been observed. The 

 study of spore-formation is, unfortunately, incomplete, but in some fila- 

 ments rounded corpuscles with a thick membrane have been observed. 

 The author justly remarks that the facts which he has brought forward 

 lend fresh support to the view that the bacterial elements vary in form. 



Bacillus muralis. — Dr. A. Tomaschek * found in a forcing-pit at 

 Biiinn that various places on tho walls were covered with slimy masses of 

 the consistence of paste, and collected into warty prominences about 2 mm. 

 high. Their colour was grey passing into violet, and in places a pure 

 violet. In spirit they became rose-coloured, and afterwards gradually 

 white. In water they fell in flakes to the bottom. Microscopical 

 examination showed that the gelatinous masses were composed of rodlets 

 resembling Bacillus megatherium. The individual rods were about four 

 times as long as thick, their ends were rounded, and they were about 

 2*5 p thick. They wero rarely straight, boing usually more or less 

 curved, but only exceptionally as much bent as a horseshoe. Each was 

 surrounded by a gelatinous transparent oval area ; and by the use of 

 finely powered indian ink it was shown that the gelatinous mass — 

 zooglcea — is produced by the adhesion of the rodlets invested with a 

 gelatinous envelope, and not by the confluence of the viscid primitive 

 masses. Only where two rodlets were separating was there any com- 

 munity of capsule ; not even in the fresh zooglcea were two rods ever 

 seen in one capsule, still less could chain-formation be observed. After 

 division the two rods separated from one another in such a way as to lie 

 side by side, and the maternal envelope disappeared. The ends of the 

 rods looked like bright spots, which might easily be mistaken for spores. 

 The appearance of cocci lying between the rods was an optical illusion 

 produced by the different positions of the bent rods. In the fresh 

 gelatin taken directly from the glass-house, increase took place by means 

 of successive fission. If the fresh mass were left in water for some days, 

 and then poured into a flat vessel from which the water was gradually 

 evaporated, endogenous spore - formation occurred. Staining with 

 methylen-blue gave favourable results. 



At the onset of spore-formation the rods consisted of 4.-6 isodiame- 

 tric cells, within which a strongly refracting body occurs, and out of it 

 the spherical spore finally appears. Within the gelatinous capsule are 

 simultaneously developed from the mother-cell a chain of 2-4-6-8 loosely 

 associated individuals. Sometimes, however, the spores separate from 

 the mother-cell, and after a period of rest, grow into rods. When 

 transferred to the vicinity of a conduit pipe, where grew a tuft of 

 Oscillaria, the bacteria grew more quickly, while all attempts at pro- 



* Bot. Ztg., xlv. (1887) pp. G65-71. 



