54 Veterinary Medicine. 



curring on the skin or mucous membranes in which there is an 

 extraordinary increase of nuclei and embryonal cells, and in 

 lymph thrown out in excess at one point, so that its central parts 

 are far from vascular tissue and nourishment, the cell elements 

 undergo a rapid increase and degradation into pus- corpuscles, 

 and its soUdified intercellular lymph undergoes granular decay 

 and liquefaction into pus. 



While the above conditions are favorable to the formation of 

 pus, the process of suppuration must now be recognized as an in- 

 fective process due to the propagation of bacteria (mainly chain 

 forms — Streptococcus pyogenes — cluster groups — Staphylococcus 

 pyogenes — and rod forms — Bacillus pyogenes) . These or other 

 bacteria are found in the pus of acute abscesses, and when absent 

 in chronic abscesses are to be considered as having perished since 

 the abscess was recent and active. Inoculation of a rabbit with 

 an excess of the pus of an acute abscess produces general puru- 

 lent infection (pyaemia) and early death ; from a medium dose 

 an abscess is produced ; while from a small dose there is no effect 

 whatever. In the latter case the bacteria are overcome and de- 

 voured by the abundance of vitally potent white blood- globules 

 and tissue cells. This pus-forming action of these bacteria ex- 

 plains the great difference in results in wounds exposed to the 

 air and those in the interior of the body and far removed from 

 air and its floating bacteria. A broken bone, with no wound in 

 the skin and little injury to parts around the fracture, is readily 

 repaired without any formation of pus, if merely kept still and 

 immovable ; whereas a broken bone, continuous with a wound 

 through the skin, always tends to form pus or become otherwise 

 infected, and is extremely dangerous even to life. The tendency 

 of every open sore is to form pus on its surface, but this may be 

 arrested and avoided by preventing the access of germs, or by a 

 free use of disinfectants and a covering which shall arrest and filter 

 out the germs. Similarly in an abscess, evacuation followed by 

 the injection of disinfectants, without the formation of any per- 

 ceptible permanent opening to the outer air, will put a stop to 

 the pus-formation. The subjection of an inflamed part to the 

 control of these pus-forming bacteria is dependent on the lowered 

 vitality and power of resistance of the inflamed tissues, and of the 

 white cells of their circulating blood. Healthy parts can success- 



