124 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



bacteriolysins), which will be considered in another place. The 

 immunity against toxins and enzymes seems to be produced by 

 identical processes, which consist in an overproduction of the 

 cellular constituents (receptors) which bind the haptophore 

 groups to the cells, these excessive receptors being secreted into 

 the blood, where they combine with the toxin or enzyme so 

 that it cannot enter into combination with the cells. 



Immune substances cannot be produced against ptoma'ins, or 

 for that matter against the vegetable alkaloids, or against 

 any chemical bodies of known constitution. Another difference 

 between the action of toxins and simpler chemical poisons is, 

 that while with the latter the effects are produced in a very 

 short time after injection, there is a latent period of several hours 

 before symptoms appear after injecting toxins. What occurs 

 during this latent period is not fully known, but that there is a 

 latent period suggests a resemblance to enzyme action. An 

 alkaloidal or other chemical poison enters the cell, and its harm 

 is done at once. A toxin combines with the cell, and then, if 

 it produces its effects by an enzymatic alteration of the cellular 

 structure, some time must elapse before the changes are great 

 enough to cause the appearance of symptoms. 



ENDOTOXINS 



By far the greater number of pathogenic bacteria do not secrete 

 their poisons as toxins into the surrounding medium, although 

 they manifestly cause disease by poisoning their host. Among 

 them are such organisms as the typhoid bacillus, pneumococcus, 

 the pus cocci, cholera vibrios, and many others. If cultures 

 of these organisms are filtered, the filtrate will be found to be 

 but slightly toxic (except for the hemolytic poisons), although 

 the bodies of the bacteria after they have been killed by chloro- 

 form or other antiseptics are highly poisonous if injected into 

 an animal. These bacteria, then, produce poisons which do 

 not escape from the cells into the culture-medium, but are 

 firmly held within them. By using various means these intra- 

 cellular toxins, or endotoxins, can be obtained independent of 

 the bacterial cells. One of these is to grind up the cells, which 

 can be particularly well done if they are first made brittle by 

 freezing at the temperature of liquid air (MacFadyen's method). 

 By very great pressure in the Buchner press the cellular con- 

 tents can be expressed. They may also be obtained by letting 

 the bacteria autolyze themselves for a short time in non-nutrient 

 fluids (Conradi, 1 et al.). Endotoxins obtained in this way are 



1 LOG dt. 



