CLASSIFICATION 9 



The second method of dealing with soluble toxic substances 

 is by a process of chemical neutralization. Here also, to a large 

 extent, the toxins are first fixed and then deposited in the indi- 

 vidual organs. The juices of the body and the component parts 

 of the cells and tissues play the part of chemical prophylactics. 

 Thus, exogenous and endogenous toxins combine with the alkali 

 and albumin of the blood, with the nuclein in the nuclei of the 

 white corpuscles, and with glycogen and the biliary acids in the 

 liver. 



Neutralization in the narrower sense, that, namely, of the 

 conversion of poisons into harmless substances, is carried on by 

 chemical processes of various kinds ; such are : oxidation and 

 reduction, hydration and dehydration, building up and breaking 

 down, c. 



A special significance attaches to the chemical affinity which 

 certain toxins display for substances normally occurring in the 

 body. In 1824, Woehler discovered the affinity of benzoic acid 

 for glycocoll, a product of the decomposition of albumin. 

 Baumann, in 1879, was able to prove that the highly toxic bodies 

 of a phenol-like nature which occur in the body and are the 

 products of the decomposition of albumin, together with the sul- 

 phates derived from the same source, have an affinity for the 

 non-toxic hydrogen ethyl sulphates which are discharged in the 

 urine. Other chemical affinities \vere discovered later as, for 

 instance, that of glycuronic acid, which is derived from the 

 carbohydrates, for mercapturic acid, and carbamic acid for urea. 

 The parts of the body where these chemical pairings take place 

 are largely unknown. We only know that in the dog, and 

 probably also in man, hippuric acid is formed in the kidney, 

 while in the herbivora it is also formed in other organs, such as 

 the liver and spleen. 



The best known example of the antitoxic function of an 

 organ is the formation of urea by the liver. Urea is the principal 

 end-product of the metabolism of albumin, but the simple 

 hydrolytic division of the albumin-molecule produces it in the 

 most minute quantities only. It comes into existence by means of 

 a synthetic process strictly in conformity with its constitution. 

 There are various hypotheses regarding this synthesis ; according 

 to one, the base of urea is ammonium carbamate, according to 

 another it is ammonium carbonate. It is certain, however, that 

 ammonia is formed in considerable quantities by the body, and 

 that the body is able to convert the ammoniacal salts which 

 reach it from the exterior into urea. The organ which is most 

 concerned in converting the toxic agents into the comparatively 

 non-toxic urea is undoubtedly the liver. Blood containing 

 ammonia is being constantly carried by the portal vein to the liver 

 (Drechsel proved the presence of ammonium carbamate in the 

 blood of dogs) and is there rendered innocuous. This can be shown 



