110 MICRO-ORGANISMS AND DISEASE. [CHAP. 



torula-form, and as such they multiply by gemmation and 

 division, and form clusters or arrange themselves in chains. 

 By and by each of these spherical elements elongates into a 

 rod, and when all elements have undergone this change we 

 have the typical smooth filament of the leptothrix-form. Some 

 of the elements in such a filament remain for a long time of a 

 spherical shape, and are much larger, looking like the sporan- 

 gium of a nostoc-alga. The most interesting forms are those 

 where an ordinary smooth filament of anthrax -bacillus at its 

 growing ends shows itself to be composed of a chain of torula- 

 elements. Such torula-forms occur also in ordinary cultiva- 

 tions in fluid media at temperatures of 20 to 30 C., but not 

 by any means so often as at ordinary temperatures and in a 

 solid medium. These torula-cells are about 0'0013 to 0'0026 

 mm. in diameter. The torula-forms are very virulent, but in 

 an animal always assume the ordinary shape of the typical 

 bacillus. 1 



As has been mentioned in treating of pigment bacilli, such a 

 torula-form has been also observed by Neelsen in the bacillus 

 that causes the colour of "blue milk ;"and Zopf 2 has observed 

 it also in cladothrix dichotoma. 



I have also observed this torula-modification in the filaments 

 of septic bacilli, in a bacillus that I found growing accidentally 

 in pork-broth. The bacillus had the same morphological 

 characters as the bacillus subtilis of hay -infusion, and also 

 formed a pellicle composed of filaments. In some of the fila- 

 ments the large torula-like cells could be seen here and there 

 interposed between cubical and cylindrical cells. 



On inoculating fluid media (e.g. broth of any kind or pep- 

 tone fluid) with the bacilli anthracis, either those of the blood 

 or of the spleen of an animal dead of anthrax, and shaking 

 the fluid so as to distribute the bacilli uniformly through the 

 fluid and exposing this to a temperature of from" 25 to 40 C., 

 it will be noticed that after twenty-four to forty-eight hours' 

 incubation the fluid is uniformly turbid, owing to the rapid 

 multiplication of the bacilli. These are shorter or longer 

 typical anthrax -bacilli. But as incubation proceeds all the 

 bacilli grow into filaments, and these being heavier sink to the 

 bottom of the fluid and form the characteristic whitish fluffy 

 convolutions. But on inoculating dilute broth, care being 

 taken that the inoculating material, whether consisting of 

 blood-bacilli, bacilli of a culture, or spores of culture-bacilli, 

 is deposited at once on the bottom of the fluid, and this is not 



1 Klein, Quart. Journ. of Microsc Science, April, 1S83. 



2 Zur Morphologic d. Spiiltpflanzen, ii. and Die Spaltpilze, Brcslau, 18S3. 



