Anthrax. 



growth of dull luster, with wavy borders, while in bouillon it forms a 



flaky, slimy sediment over which the liquid remains clear or only 



slightly cloudy. The bacilli may also multiply and form spores in 



greatly diluted albuminous solutions and in ordinary 



water. 



In the animal body anthrax bacilli multiply ex- 

 clusively by direct division, and in this way short chains 

 of 3, 4 or 8 links result in the tissue fluids (Fig. 2). 

 On artificial media very long chains develop by similar 

 division, and the bacilli, which on these media are 

 usually more slender, grow even to form long, homog- 

 enous threads, which subse<iuently become divided by 

 cross sections into chains of bacilli (Figs. 5 and 6). 



In the presence of a sufficient (juantity of oxygen 

 and at a temperature of 43° C. maximum or 12 C. mini- 

 mum spores develop in the bacilli (Figs. 5 and 6). One 

 pole of the bacillus separates by a cross section from its 

 body and incloses one or a half of a chromatin granule ; 

 after the disappearance of the granule the fertile pole 

 segment separates from the wall whereupon its central 

 part forms the body, and the peripheral part forms the 

 covering of the spore (Preisz). Under favorable condi- 

 tions the oval spore swells, its covering becomes extended 

 and soon forms one of the poles. The young germ then 

 makes its appearance and grows, developing into a 

 bacillus, which later again propagates either by fission 

 or spore formation. (Spores never develop in the tissue 

 fluids of the living animal, in the unopened carcass, or 

 inside of the meat of slaughtered animals. ) 



According to Brotiu bacilli produce spores in the intestinal 

 tract of the dog which is only slightly susceptible to anthrax. 

 According to Oppermann spores form in the caecum of the rabbit 

 and according to Plana in the intestinal tract of birds. 



At 42-43 °C., as well as on media containing substances 

 which retard their growth (for instance, 0.1% carbolic acid), and 

 by limiting the air supply, anthrax bacilli may temporarily, or 

 forever, lose the faculty of spore formation, (so-called asporo- 

 genic modification [Behring, Roux. Pfersdorf]). On artificial 

 media various irregular forms develop occasionally after 2 to 3 

 days (club-, pear-, and screw-forms), although the culture may 

 retain its original virulence (Lignieres & Durrien). 



Fig. 3. Six-day 

 old gelatin cul- 

 ture of the an- 

 thrax bacillus. 



Tenacity. There is a marked difference in the tenacity of 

 the bacilli and spores. While the bacilli are less resistant, the 

 spores are only destroyed by substances which have a very ener- 

 getic action. 



The bacilli are destroyed by drying in thin layers in the sunlight in from 6I/2 

 to 15 hours, in thick layers and in the dark in from 2 to 3 weeks, and by heating 

 to 5.5-58°C. in 10-1.5 minutes. In dried blood, however, they may remain virulent 

 for one month or longer, and may then form spores on addition of water and 

 under proper temperature conditions (Bongert). They are only destroyed in dried 

 blood when heated to 92 °C. for 2^2 hours (Momont). On the other hand, they 

 die in putrid blood, particularly in anaerobic putrefaction inside the unopened 

 carcass, in warm weather in 2 to 3 days. The bacilli manifest a great resistance 

 against low temperatiires, as for instance, at 10°C. they are destroyed in 24, and at 

 24°C. in 1.5 days (Klep7of). In the gastric juice they die in 15-20 minutes; in 

 pure or putrid water in 1 to 2 days. Ichor destroys them if mixed with anthrax 

 blood in 2-4 hours (Schipp). The ordinary disinfectants destroy the bacilli even 

 in high dilutions (Koch). 



Simple drying does not destroy the spores at all, so that in such condition, 

 for instance, when dried on silk threads, they may remain germinative for 18 Vi 



