406 BACILLI OF NO KNOWN PATHOGENIC PROPERTIES. 



dense balls are formed ; in these balls the threads become 

 broken up into short or long pieces, varying from 5 to 

 50 p. in length ; the short portions grow and bend almost 

 always laterally from the original direction of the thread. 

 Formation of After some time growth ceases, and the organism be- 

 bodies Ca comes broken up into spherical individuals, described 

 by Kurth as cocci. The rows of cocci remain in the 

 gelatine united in the form of balls ; when sown on new 

 gelatine, rods and threads are again formed within 16 

 hours. The round forms appear when the nutrient ma- 

 terials are becoming exhausted ; they are not able to 

 multiply by fission, but they can under favourable cir- 

 cumstances sprout out in the form of short rods. 

 Biscuit-shaped pairs of cocci also occur, which are, 

 however, regarded by Kurth only as a more or less 

 advanced stage of the subdivision of a rod into two 

 cocci. These biscuit-shaped pairs at times show swarm- 

 ing movement. The behaviour of the cocci when 

 dried appears to be especially important ; while the 

 rods die in the dry state after 52 to 108 hours these 

 Are these coccus forms live for 17 to 26 days. The cocci also 

 ^ 1 ores? re ^ u their vitality for a very long time, for even more 

 than 82 days, in the exhausted nutrient solution. From 

 the biological characters mentioned above, and in corre- 

 spondence with our previous definition of micrococci 

 and spores respectively, Kurth looks on these spherical 

 forms as spores. On the other hand, we have the fact 

 that the round cells of this bacterium are not much more 

 highly refracting than the bacilli, that they stain intensely 

 with aniline brown, and that there is no difference between 

 them and the bacilli in their resisting power to high 

 temperatures. Nevertheless a higher refracting power, 

 difficulty in staining, and resistance against heat have 

 not as yet been looked on as indispensable for the 

 assumption that any given cell is a spore, and as a 

 matter of fact such an assumption cannot be made so 

 long as the general characters have been studied on only 

 a very small proportion of the existing spores. The only 

 two important criteria which must be required on the 

 part of a spore are a certain resistance against external 



