SrECIFIC DIFFERENCES OF ACTION. 13 



organisms and those concerned in the process of digestion and fer- 

 mentation, it may be pointed out that after one micro-organism has 

 completed its task another may step in and continue the process of 

 breaking down. How frequently a pyaernic condition supervenes on 

 a tubercular. How often has a patient suffering from tubercular 

 abscess of the kidney or of the lungs, succumbed at last (if not carried 

 off by acute tubercular disease) to pyaemia, and -pyaemia in which the 

 symptoms are extremely well defined, where a poison much more 

 active and far reaching in its character than the tubercular poison is 

 rapidly formed on the introduction of a fresh organism into dead, 

 but hitherto inactive or non-irritant, structures. 



That these special products of bacterial fermentation do occur 

 can scarcely now be denied, nor that, where the ferment is found, the 

 organism secreting it must first have been present, not necessarily in 

 the position jn which the ferment is found — for the ferment may be 

 much more diffusible, and may pass from point to point much more 

 readily than the organism to which it owes its origin, but at some 

 point whence absorption of the ferment could take place. 



Specific Differences of Action. 



11. The activity of the ferment undoubtedly varies gready in different 

 cases, and the results of the action of these ferments on the tissue 

 must vary, perhaps not so widely as the ferments themselves, but so far 

 that they may be roughly classified. On the one hand, there are the 

 effects produced in the so-called " granulomata," where an irritant 

 action is set up, followed at first by a proliferation of the connect 

 tive tissue or other cells, and then by a breaking down and case- 

 ation of the proliferated mass, the appearances varying according to 

 the tissue affected and the position of the growth in this tissue. These 

 changes take place slowly. Going to the other extreme, cases of 

 acute septicaemia are sometimes met with, in which the patient is 

 carried off in the course of a few days, and where \k\t post mortem 

 changes are of the slightest and most general character. In such 

 extreme conditions there are, on the one side, the slowly growing and 

 slowly multiplying bacilli, which give rise to an irritant product, but 

 one the action of which is fairly definitely localised, and is carried on 



