DEFENSE AOAIXST ISOliGANIC I'OISOSS 241 



by repeated siihcutaiicous injecdoiis of sul)letluil doses, 'riicic is, 

 however, reason to question the authenticity of the reputed toku-ance 

 of habituds to arsenic (Joachimoglu).-" Antimony does not produce 

 tolerance in experimental animals (Cloetta).-' The manner in which 

 various inorganic ions antagonize the physiological action of one 

 another (e. g., sodium and potassium, calcium and nuignesium) is 

 still an important problem. -'- 



Free acids and alkalies are partly neutralized by the alkaline and 

 acid contents of the gastro-intestinal tract, partly by forming com- 

 pounds with the proteins, and partly by the alkalies and carbonic acid 

 of the blood stream. (See "Acid Intoxication," Chap, xx.) Phos- 

 phorus^^ and sulphides arc oxidized after absorption into phosphoric 

 and sulphuric acid, which are in turn neutralized by the alkalinity 

 of the blood^and tissues. Lillie-^ has called attention to the close, 

 palisade arrangement of the nuclei of the epithelium lining the ali- 

 mentary tract, which makes it necessary for all substances absorbed 

 to pass through the zone of their active oxidative influence, a fact 

 uncloubtedly of great importance in the defense of the body. 



Reduction of iodic acid, chloric acid, hj-pochlorous acid, and their 

 salts occurs in the body, resulting in their conversion into the much 

 less toxic iodides and chlorides. Tellurium compounds are also re- 

 duced and rendered insoluble. This reaction occurs to some extent 

 in the intestines; how much in other organs is unknown. 



Methylation, the addition of CH3 groups, is observed in poisoning 

 by tellurium, which is eliminated in the breath as methyl telluride, 

 and also in the sweat and feces. ^^ Selenium, pyridine, and some other 

 substances also combine with methane. The source of the methane is 

 possibly in the xanthine molecule. 



Summary. — There are, therefore, three chief reactions used against 

 inorganic poisons in the body, oxidation, reduction, and splitting off 

 of water; neutralization of acids or alkalies and the formation of al- 

 buminates and sulphides being included under the last heading, since 

 in these reactions the splitting off of water is an essential step. 



ORGANIC POISONS 



In the case of organic poisons an ecjually small number of primary 

 reactions is emploj-ed in their detoxication, but in more complicated 

 manners and combinations corresponding with the complexity of 

 organic compounds. 



-' Arch. exp. Path. u. Phann., 1911 (64), 352. 



•" See Osterhout, Proc. Phil. Soc, 1916 (55), 533. 



-' Increased tolerance to phosphorus maj' be obtained by repeated small doses, 

 but it lasts only while the poison is being given continuously (Oppel, Ziegler's 

 Beitr., 1910 (49), 543). Accompanying the tolerance are structural changes in 

 the liver cells to which are ascribed some significance bv Oppel. 



-* Amer. Jour. Physiol.. 1902 (7), 412. 



" See Mead and Gies, Amer. Jour. Phvsiol., 1901 (5), 105. Caffein may be 

 demethylated in the liver. Kotake, Zeit., physiol. Chem., 1908 (57), 378. 



16 



