CHAPTEE XI 



TOXINS AND ANTITOXINS. 



Through. Ehrlich the word toxin has come to 



Definition 6 . . 



of Toxin, have a special significance, being applied only to a 

 certain type of toxic substances. According to his 

 original conception they have the following prop- 

 erties : 



1. They are extremely labile substances which 

 occur as secretion products of vegetable or of ani- 

 mal organisms. 



2. Their chemical nature is unknown. The im- 

 possibility of obtaining them in pure form and 

 their great lability render them insusceptible to 

 ordinary chemical analysis. 



3. An analysis of a toxin may be reached at 

 present only through the medium of biologic ex- 

 periments. 



4. Immunization with toxins yields antitoxins. 

 It has not been possible to obtain antitoxins for 

 inorganic poisons, glucosids and alkaloids 

 (morphin, strychnin, etc.) 



5. In contrast to well-defined chemical poisons, 

 the action of toxins is characterized by a latent or 

 incubation period. That is, following the introduc- 

 tion of a toxin, a certain period of time elapses 

 before toxic symptoms appear, and this period is 

 greater than the time logically required for the 

 absorption of the toxin through the circulation. 1 



1. Recent work indicates that the long incubation period 

 of tetanus may depend, at least in part, on the length 

 of time required for the toxin to reach the ganglion cells 

 through the axis cylinders of the motor nerves. 



