PycBmia and Septimmia. 19 



Pyaemia. Causes. The causative microbes are most commonly 

 staphylococcus pyogenes aureus, or albus, the streptococcus 

 pyogenes, and less frequently bacillus pyocyaneus, bacterium coli 

 commune, and probably any pus producing microbe. Many con- 

 ditions must however be accepted as contributing to the general 

 infection. 



Inoculation on a mere abrasion or surface sore is not to be 

 dreaded so much as if the virus is lodged subcutaneously or in a 

 deep wound. The ready escape of the toxic products, the active 

 leucocytosis which takes place in the granulations, and the action 

 of the oxygen of the air are more or less protective in the ex- 

 posed sores. 



The native susceptibility of the subject, — horse, ox, — conduces 

 to the disease, while the insusceptibility,— bird— tends to obviate it. 



The debility of the system or of individual tissues attacked, lowers 

 the resistant power, and especially that of leucocytosis, and thus 

 favors survival and encrease of the microbes and their chemical 

 products. Thus the shock succeeding a serious operation, the 

 general depression attendant upon severe illness, or the poisoning 

 by narcotizing ptomaines and toxins, may easily become the extra- 

 weight which causes the system to succumb. On the contrary, 

 pre-existing or long standing disease, with consequent general 

 debility appears at times to prove to some extent a protective 

 factor, the previous exposure to the invading germ having edu- 

 cated the leucocytes to resist the toxins and to produce the de- 

 fensive sera which neutralize the latter or keep the invading mi- 

 crobes in check. A measure of immunization has been secured. 



The resulting immunization cannot be looked on as very per- 

 fect, nor permanent, as a specially strong inoculation by a 

 virulent microbe, or large dose, or different conditions of hfe, 

 will entirely overcome it, and the pysemic fever appears. Yet 

 in chronic cases of secondary abscesses from a deep source of 

 infection, the resistance is often such as to ward off febrile 

 pyaemia. In a horse with primary abscess situated deeply under 

 the humerus, free evacuation and heaUng of the wound, have, in 

 my experience, been followed by the formation of abscesses in 

 distant points for a period of seven years, but without any 

 marked febrile reaction. 



The complex nature of the infection appears at times to over- 

 come the vital resistance more effectively than will the presence 



