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whose collaboration he afterwards produced so many valuable 

 works. Nencki and Sieber showed that when benzene was 

 administered to an animal the proportion of phenol that could 

 be detected in the urine after hydrolysis with acid to destroy 

 the phenyl sulphuric acid, was a constant for any particular 

 animal. This constant was, furthermore, independent of the 

 nutrition of the animal ; the ratio of the phenol to the benzol 

 administered was constant for a given animal, whether that 

 animal were well fed or in a fasting condition. Certain toxic 

 bodies are known, however, to diminish the oxidative processes 

 of the body; amongst such poisons may be mentioned arsenic, 

 phosphorus, antimony, etc. Nencki and Sieber showed that if 

 benzene be ingested after administration of such poisons, the 

 proportion of phenol excreted was much diminished. They 

 made use of this fact for devising a process for measuring 

 physiological oxidation in the body in health and disease, and 

 applied it in the investigation of oxidation in cases of leukaemia 

 and of diabetes mellitus. In the former case they found a 

 general depression of oxidation ; in the latter case, however, 

 they found that oxidation was normal, and they concluded 

 therefore that the excretion of sugar must be due to other 

 causes than the depression of oxidative functions. 



Amongst other substances of which the behaviour in the 

 animal body was investigated may be mentioned the various 

 aromatic hydrocarbons with side chains, the various phenols, 

 acetophenones and allied ketones, and various esters. 



The substituted benzene derivatives were found to undergo 

 oxidation when administered to an animal. Toluene was 

 oxidised to benzoic acid and excreted chiefly in the form of 

 hippuric acid, the conjugated glycine derivatives. In hydro- 

 carbons containing more than one side chain, it was found that 

 one and one only of the side chains was oxidised, and substituted 

 benzoic acids were excreted in a conjugated form, either as 

 glycuronates or as substituted hippurates. Phenols were 

 oxidised to bodies containing a larger number of phenolic 

 hydroxyl groups, whereas benzoic acids and substituted benzoic 

 acids were not further oxidised, but excreted either as gly- 

 curonates, or in some other conjugated form. Naphthalene 

 was oxidised to naphthol. From these results Nencki makes 

 important pharmacological generalisations. He shows that 

 those bodies which undergo oxidisation, and thereby deprive 



