XIII. 
BACILLI WHICH PRODUCE SEPTICAIMIA IN 
SUSCEPTIBLE ANIMALS. 
WHEN, as a result of accidental (natural) or experimental inocula- 
tion, a microdrganism is introduced into the body of a susceptible. 
animal which is able to multiply in its blood, producing a general in- 
fection, we speak of this general blood infection as a septiccemia. 
When pathogenic microérganisms which are unable to multiply in 
the blood establish themselves in some particular locality in the ani- 
mal body which is favorable for their growth, and by the formation 
of toxic products, which are absorbed, give rise to general symptoms 
of poisoning, we designate the affection toxemia. As examples of 
this mode of pathogenic action we may mention diphtheria and 
tetanus. As a rule, the various forms of septicemia are quickly 
fatal, and, as the microdrganisms to which they are due multiply in 
the blood of the infected animal, this fluid possesses infectious pro- 
perties, and, when inoculated in the smallest quantity into another 
susceptible animal, reproduces the same morbid phenomena. A typi- 
cal example of this class of diseases is found in anthrax, to which 
disease a special section has already been devoted (VIII.). But in 
this and other forms of septicemia subcutaneous inoculations do not, 
as a rule, result in the immediate invasion of the blood by the para- 
sitic microérganism. Often a local inflammatory process of consider- 
able extent is first induced ; and in some cases general infection only 
occurs a short time before the death of the animal, depending, per- 
haps, upon a previous toxemia from the absorption of toxic products 
developed at the seat of localinfection. The pathogenic action, then, 
in acute forms of septicaemia appears to result, not alone from the 
presence and multiplication of the pathogenic microdrganism in the 
blood, but also from the toxic action of products evolved during its 
growth. 
Some of the pathogenic bacilli of this class now known to bac- 
teriologists have been discovered by studying the infectious diseases 
induced by them in lower animals among which these diseases pre- 
vail naturally—?.e., independently of human interference. Many 
