304, OTHER GERM DISEASES 
the only thing that multiplied and remained in his later flasks 
were the bacteria present in the original drop of blood. Never- 
theless, he found that though he continued these inoculations 
indefinitely, every flask was equally virulent, and a small drop 
of the culture would inevitably produce anthrax in a susceptible 
animal in a very few hours, the development of the disease being 
always accompanied by the growth in its blood of the bacilli in 
countless myriads. These results left no loophole for criticism, 
proving that this bacterium was the cause of anthrax, and thus 
for the first time demonstrating that an infectious disease was 
produced by a bacterium multiplying within the body of the 
animal in which it grows as a parasite. 
The bacterium in question, Bact. anthracis, is a rod of moderate 
size (Fig. 51). It multiplies by repeated division, the elements re- 
maining attached to form long chains. Sometimes these long 
threads show no signs of the divisions, and in certain media they 
form marvelously twisted and contorted masses. When in an 
active growing condition, this bacterium is readily killed by 
ordinary disinfecting agents and by a moderate heat, a tem- 
perature of about 160°F. easily destroying the rods. But it 
produces resisting spores which can easily be distinguished inside 
the rods as clear, glistening bodies. It is their resistance to ordi- 
nary agents that makes anthrax so persistent, and this high re- 
sistance must be borne in mind when the attempt is made to 
disinfect a stable which has been occupied by an animal having 
this disease. These spores will resist the action of 5 per cent. 
carbolic acid solution for half an hour, or a r per cent. solution of 
corrosive sublimate for about the same length of time. Few 
other living bodies can resist such treatment. The spores will 
also resist a temperature of about 280°F. for two or three hours. 
When immersed in liquid they are much more easily killed, since 
the temperature of boiling, if maintained for a few minutes, is 
commonly sufficient to destroy them. When dried the spores 
may remain alive for a long time, many years at least, and yet 
