86 PATHOGENIC BACTERIA. 



staphylococcus suppurations, in which the entire process 

 is local and limited to the field of bacterial action; and 

 second, by typhoid fever, in which the majority of the 

 organisms remain in the intestinal and mesenteric lesions, 

 where the local damage is marked, though the general 

 histologic changes show that a mild intoxication prob- 

 ably also takes place. 



In tetanus and diphtheria we find bacteria whose 

 products are freely soluble, so that the damage done by 

 the intoxication vastly outweighs that of the local lesions. 



In the Bacillus anthracis we have a micro-organ- 

 ism whose toxin-producing ability is very uncertain. 

 The damage done by its presence may be entirely de- 

 pendent upon its tendency to blockade the capillaries 

 and its ready affinity for oxygen. It is certainly largely 

 dependent upon its great vegetative ability. Other bac- 

 teria of the septic class seem to furnish more or less de- 

 monstrable poison. 



Toxins. — Concerning the poisons generated by the 

 bacteria we are at present in position to say very little. 

 They are probably all proteid substances, most of them 

 being properly classed among the toxalbumins. The 

 toxins of diphtheria and tetanus, which have been studied 

 more closely than any of the others, seem to belong to a 

 separate class of poisons which do not give any of the 

 albumin reactions. As a rule, the bacterial poisons are 

 delicately organized, being destroyed by temperatures 

 above 6o° C, by exposure to light and air, and by pro- 

 longed keeping. An exception to this rule seems to 

 occur in the semi-artificial toxic product of the tubercle 

 bacillus known as tuberculin, which is not injured by 

 heating to ioo° C. for hours at a time. The toxins seem 

 to be soluble, leaving the protoplasm of the bacteria to 

 appear in the filtered fluid in which they have grown, as 

 in tetanus and diphtheria bacilli cultures ; and insoluble, 

 present only in the bodies of the bacteria, as in the chol- 

 era spirilla, typhoid fever bacillus, and pyogenic cocci. 



The physiologic action of the toxins varies with each 



