TOLERANCE TO POISONS 239 



stimulus of the poison, just as they are in the case of immunization 

 with toxins, with the difference that the combining substances are 

 not thrown off into the blood. For example, it has been claimed that 

 arsenic is ordinarily combined and held in the liver by a nuclcoprotein, 

 and the suggestion has been made that in arsenic habituds this nuclco- 

 protein is increased in amount. Again, saponin seems to act upon the 

 cholesterol of the red corpuscles, and Kobert observed increased resist- 

 ance to the action of saponin exhibited by the serum of immunized 

 animals, which he attributes to an increased amount of cholesterol, 

 perhaiis liberated by the corpuscles decomposed by the injected poison, 

 or perhaps produced in excess by the tissues. Wohlgemuth^ has also 

 suggested that in the case of poisoning with large amounts of sub- 

 stances which combine with glycuronic acid (e. g., lysol), excessive 

 quantities of this substance are formed by the cells and excreted into 

 the blood, where they neutralize the poisons in much the same manner 

 as the antitoxins neutralize toxins. 



But besides these scanty examples of tolerance to poisons, the body 

 possesses a number of methods for opposing manj'- other poisons with 

 more or less success; and, poisons invariably acting chemically, the 

 defenses are in turn largely chemical. We have elsewhere referred to 

 the destructive action of the enzymes of the digestive tract upon bac- 

 terial and similar poisons; this means of defense cannot apply to 

 non-protein chemical substances except possibly glucosides and toxic 

 lipoids. But the acidity of the gastric juice, the alkalinity of the 

 bile and pancreatic juice, and the precipitating effect of the hydrogen 

 sulphide formed in intestinal putrefaction are all factors that help 

 to neutralize or prevent the absorption of certain poisons, their total 

 efficiency, however, being on the whole very slight. After absorption 

 of a poison a large series of chemical reactions and physiological proc- 

 esses is brought into play, and there are few poisons indeed whose 

 harmful influence is not more or less decreased by these means. Ko- 

 bert" classifies these protective processes as follows: 



1. Rapid elimination, either before absorption by means of diarrhea and 

 vomiting, or by the same means after absorption in case the poisons are excreted 

 into the digestive tract (e. g., morphine, venoms, antimony, and many other 

 metals). Many poisons are very rapidly eliminated by other routes (e. g., anes- 

 thetics, curare), in some instances causing harm, particularly to the eliminating 

 organ (e. g., kidneys in phenol poisoning, intestines in ricin poisoning). The 

 routes and conditions of elimination of poisons have been fully discussed by 

 Lewin." 



2. Deposition and Fixation in Single Organs or Tissues. — In this respect the 

 liver is especially important, probably because of its location and function as a 

 filter for all the blood coming fresh from the alimentary tract." The manner and 



» Biochem. Zeitschr., 1906 (1), 134. 



^ "Lehrbuch der Intoxikationen," Stuttgart. 



10 Deut. med. Woch., 1906 (32), 169; see also Mendel et al., Amer. Jour. Physiol., 

 1904 (11), 5; 1906 (16), 147 and 152. 



" Concerning the detoxicating function of the liver see Woronzow, Dissertation, 

 Dorpat, 1910; Rothberger and Winterberg, Arch, internat. Pharmacodyn., 1905 

 (15), 339. 



