852 SUMMABY OP CUBRENT RESEARCHES RELATING TO 



bottom ; (4) the nutrient fluid always remains clear ; (5) under low 

 powers the young culture appears S-shaped and strongly swollen in 

 the middle. It grows on all kinds of serum, but not on the white 

 of egg. 



Dr. Koch regards the bacillus of tuberculosis as a true parasite, in 

 contrast to other pathogenous bacteria. It goes through its whole 

 course of development, up to the production of spores within the body. 

 He believes it has no genetic connection with any other form of 

 bacterium. 



Development and Pathogenous Properties of a Bacterium.* — 

 Herr G. Hauser describes a pathogenous bacterium obtained from the 

 putrefaction of a calf's heart at 30° C. under ordinary conditions. An 

 infusion after eight days showed a great quantity of bacteria, which, 

 however, when cultivated in the ordinary way, did not exhibit any 

 great power of causing deliquescence of the substratum. After 

 exposure for another eight days to the ordinary temperature of a 

 room there appeared in the infusion a bacterium which grew with 

 extraordinary rapidity, causing rapid deliquescence of the gelatin on 

 which it was cultivated. 



After cultivation on gelatin for twelve hours, a great quantity of 

 small oval bacteria were to be seen floating on the substratum, often 

 linked together in pairs ; the whole of the rest of the surface being 

 completely covered by colonies of irregular form consisting of a single 

 layer of well-developed rods and short filaments. These colonies 

 were in continual rapid motion, some of the rods constantly leaving 

 them in the form of an elongated well-defined group, which glided 

 rapidly over the free surface of the gelatin, then joining with others 

 or with another colony. Each of these groups consists of from three 

 to five parallel rows of spindle-shaped rods. Their movements are 

 very peculiar, resembling those of individual bacteria, and are in no 

 way due to motions in the substratum. Other groups again did not 

 become separated, but reunited themselves with the colony from which 

 they had partially detached themselves. 



The deliquescence of the gelatin by these bacteria took place very 

 rapidly, being completed in from twelve to twenty-four hours, with 

 the formation of a whitish sediment. In this condition it contained a 

 number of minute bacteria endowed with a dancing movement, and 

 closely resembling Bacterium Termo. When cultivated on gelatin, 

 these developed gradually from shorter to longer rods and filaments, 

 which swarmed over the entire surface of the nutrient gelatin, causing 

 it to deliquesce. From these swarming colonies were developed longer 

 filaments endowed with rapid motion, which gradually divided into 

 shorter elements, and finally came to rest, passing then into an hour- 

 glass-like form, from which were developed the peculiar colonies 

 already described. 



This peculiar bacterium causes very rapid decomposition in the 

 flesh of animals, accompanied by the development of stinking gases ; 

 the products of decomposition appearing to have poisonous properties. 



* SB. Phys.-med. Soc. Erlangen, 1884, pp. 156-71. See Biol. Centralbl., v. 

 (1885) p. 36. 



