INORGANIC POISONS 159 



by which this fixation is brought about are unknown. Accord- 

 ing to Slowtzoff 1 arsenic is fixed by the nucleus in a very firm 

 combination ; 2 mercury by globulins in a less stable combination ; 

 copper by the nucleins, but less firmly than the arsenic. Other 

 poisons, chiefly alkaloids, are probably combined with bile acids. 

 Possibly some poisons combine with glycogen. These corn- 

 pounds are but slowly broken up, and thus the poison reaches 

 the more susceptible and more important tissues in a relatively 

 diluted condition. The bones seem to hold in harmless form poi- 

 sonous fluorides, and to less extent arsenic, barium, and tungsten, 

 which persist in the bones for a great length of time. Leucocytes 

 are possibly important binders of poisons, perhaps through 

 combination with their nucleins, 3 but storage in these labile cells 

 is necessarily of relatively brief duration. Many poisons com- 

 bine with the inorganic constituents of the tissues ; e. g., barium 

 and various aromatic substances with SO 4 ; silver with Cl, etc. 



3. Combination with substances formed or contained in the 

 tissues ; the resulting substance being less toxic than the poison 

 alone. This method will be considered at greater length in connec- 

 tion w T ith the related, often associated, method of defense ; namely : 



4. Chemical alteration, with or without subsequent com- 

 bination with other substances, by such means as oxidation, 

 reduction, hydrolysis, and neutralization. 



5. Impaired absorption should also be considered as a means 

 of defense against poisons. This may depend upon the injury 

 to the gastro-intestinal tract produced either by the poison itself 

 or by some independent pathological condition. Cloetta considers 

 impaired absorption important in acquired immunity to arsenic 

 (see below) and it may also modify the effects of other poisons. 



The chemical reactions employed in defense against simple 

 chemical poisons have been particularly considered by E. 

 Fromm, 4 whose outline is here partially followed, and to which 

 the reader is referred for bibliography. 



INORGANIC POISONS 



Metallic poisons, such as lead, silver, mercury, and arsenic, 

 are made insoluble, particularly by forming compounds with 

 proteids in the alimentary tract, intestinal walls, blood, or internal 



1 Hofmeister's Beitr., 1901 (1), 281 ; 1902 (2), 307. 



2 Denied by Heffter (Arch, internal, de Pharmacodyn., 1905 (15), 399), 

 who considers it more a physico-chemical process. 



3 Stessano, Compt. Eend. Acad. Sci., 1900 (131), 72. 



4 " Die chemischen Schutzmittel des Tierkorpers bei Vergiftungen," Strass- 

 burg, Karl Triibner, 1903. See also re'sume' by Ellinger, Deut. med. Woch., 

 1900 (26), 580. 



