ORGANISMS WHICH PRODUCE DISEASE 57 



in the pleural sacs around the lungs, the pericardial sac in which 

 the heart lies, in the meninges around the brain, etc., or in a 

 joint or similar cavity. 



Toxaemia : is a condition in which the toxins or poisons pro- 

 duced by organisms or other agents pass into the circulating 

 blood, and so come to act on all the tissues of the body, some- 

 times injuring them all, sometimes picking out some special 

 tissue, as in the case of tetanus toxin and nervous tissue in 

 Lockjaw. 



Septicaemia : is where the disease-producing organisms 

 themselves pass into the blood, and in its severer forms (in 

 anthrax, plague-septicaemia, etc.), proliferate there in enormous 

 numbers and are therefore found throughout all the tissues of 

 the body. 



Septicaemia and toxaemia are often combined in the same 

 disease. 



Pyaemia: when suppurative inflammation attacks a vein, 

 the blood within it may become thrombosed or solidified. The 

 organism may then infect and cause softening of this throm- 

 bus or solidified blood, which may be carried along the veins 

 and be distributed throughout the body in the circulating 

 blood. Portions of the softened and infected material so 

 carried may settle down in any part of the body and cause the 

 formation of abscesses, e.g. in the lungs or other organs, joints 

 or bones. 



CHAPTER VII 



SOME OF THE COMMONER ORGANISMS WHICH 

 PRODUCE DISEASE 



Group of Organisms causing Wound-Infection, Inflamma- 

 tion, and Suppuration 



As explained above, the same organism may in one instance 

 produce suppuration, localised as abcesses, boils, or carbuncles ; 

 in another a spreading inflammation such as erysipelas and 

 other forms of cellulitis (inflammation of the cellular connective 

 tissues, especially those of the skin ;) or again, a generalised 

 infection such as a septicaemia or a pyaemia the form of 

 disease so produced depending upon the virulence, number, and 

 method of introduction of the organisms into the body on the 

 one hand, and upon the susceptibility or resistance of the 

 tissues to the attack on the other. 



Some of these organisms of wound-infection are very common 



