224 A MANUAL OF BACTERIOLOGY 



As will be gathered from the descriptions of the individual 

 organisms, suppuration may be set up by inoculation with 

 several species, and a number of experiments by various 

 observers, carried out by inunction, subcutaneous inocu- 

 lation, and inoculation in the serous cavities and circula 

 tion, have conclusively proved that this is the case, not 

 only in animals, but also in man. 



A problem of great importance is whether micro- 

 organisms are usually the cause of suppuration, or whether 

 mechanical injury, chemical agents, etc., can also produce 

 it. Mechanical injury alone does not seem to be capable 

 of inducing pus production, but it is otherwise with regard 

 to chemical agents. For a long time considerable differ- 

 ence of opinion existed and discordant results were 

 published. These discrepancies have now been explained, 

 and are found to depend upon the method of experiment 

 and the particular animal and chemical agent employed 

 That chemical agents should produce suppuration might 

 be expected, for it would be against analogy, derived from 

 all other bacterial diseases, if the pyogenic organisms do 

 not produce suppuration through the chemical substances 

 formed by, or present within, their cells, and if these 

 chemical substances act thus, why should not other 

 chemical substances be found to act in a similar way ? 



In experiments with chemical agents the greatest care 

 has to be taken to exclude the entrance of micro-organisms. 

 This is best done by sealing the sterilised substance in 

 sterilised fusiform glass tubes and introducing these under 

 the skin or into the tissues with strict aseptic precautions. 

 When the wounds have completely healed the tubes are 

 broken by pressure and their contents allowed to diffuse 

 nto the surrounding tissues. 



Sterilised cultures (above a certain amount) of the 

 Micrococcus pyogenes and a crystalline body, phlogosin, 

 obtained by Leber from its cultures, produce abscesses on 



