42 INFECTION 



moiety for each is non-toxic but represents the part which calls 

 forth specific antibodies. The characteristic infectious phenomena 

 of each disease are therefore due to the non-toxic part of its 

 molecular construction. It has been shown that protein 

 cleavage products can cause fever if injected into animals. 



Cholera and typhoid organisms do not produce soluble toxins 

 in the body, but when they are disintegrated therein, soluble 

 poisons (intracellular) are liberated. 



Bacterioprotein or plasmins are albuminous bodies produced 

 by bacteria, are not altered by heat, and produce fever and in- 

 flammation. The best examples of these are mallein a product 

 obtained from old cultures of glanders bacilli, and the original, 

 or old tuberculin of Koch. 



Toxins or toxalbumins are soluble, non-crsytallizable, non- 

 dialyzable bacterial products which are removable by filtration 

 from the bacteria, and which are thermolabile. 



These various poisons produce many of the clinical pathological 

 entities and symptoms, known to physicians. Their highly 

 complex molecular structure enables a group of atoms in the 

 toxic molecule to unite with a certain other group of atoms in 

 the protoplasmic molecule of a body cell. The latter is either 

 killed outright, or else is stimulated to produce other free groups 

 of combining atoms (lateral chains) which may unite with other 

 toxic groups. 



Various kinds of cells are attacked in infective processes. 

 Leucocytes may be degenerated, forming pus; red blood cells may 

 be dissolved, causing anaemia; important nerves may be degener- 

 ated; or muscle fibers of the heart may undergo fatty degeneration 

 and die. Again, mechanically important serous cavities may be 

 filled with serum, interfering with normal functions of the en- 

 veloped organs. The heart orifices may be closed partially or 

 emboli may form, or false membranes block the air passages, and 

 a hundred other pathological changes may be wrought by these 

 toxins. 



