458 LECTURE XIX. 



Here, the object of the oxidation is not so apparent, because the combina- 

 tion with sulphuric acid takes place just as easily before as after. In other 

 cases it is necessary for the poisonous substance to be oxidized first, in 

 order to make it possible for the combination with sulphuric acid to take 

 place. Thus we know that benzene is first changed into phenol, 1 indole 

 to indoxyl, and skatole to skatoxyl. 2 Acetanilide appears in the urine as 

 p-aminophenol, as p-acetylaminophenol, and as the anhydride of hydroxy- 

 phenylcarbamic acid partly united with sulphuric acid and in part with 

 glucuronic acid. 3 In the group of glycocoll conjugates we have xylene 

 converted to toluic acid : 4 



CH 3 . C 6 H 4 . CH 3 + 3 = CH 3 . C 6 H 4 . COOH + H 2 O. 



Mesitylene is changed into mesitylenic acid, 5 and cymene to cumic acid. 61 

 For conjugation with glucuronic acid, similarly, the cells act upon poi- 

 sonous substances in various ways. Thus, for example, o-nitrotoluene 

 is changed to nitrobenzyl alcohol, which then unites with glucuronic acid: 7 



N0 2 . C 6 H 4 . CH 3 + = N0 2 . C 6 H 4 . CH 2 OH 

 N0 2 . C 6 H 4 . CH 2 OH + C 6 H 10 7 = NO 2 . C 6 H 4 . CH 2 . C 6 H 9 6 + H 2 O 8 



We have distinguished in the case of all the organic foodstuffs two 

 different functions which they have in the cells of the animal organism. 

 On the one hand they may serve as sources of energy, while on the other 

 hand they may serve as material for the construction of new tissue. Like- 

 wise it is possible for the inorganic salts to develop energy by physical 

 methods; but their chief use, however, is in the formation of new material, 

 whether it be due to an intimate union with organic material, or whether 

 the unchanged inorganic salt is in an indispensable constituent of the cells 

 and that their activity only results from its presence. Of oxygen we 

 have spoken of but one function, that of making energy available. The 

 question naturally arises whether oxygen itself is not used as building 

 material in the construction of new cells? There are, as a matter of fact, 

 certain observations which seem to indicate that the entrance of oxygen 

 into the contents of the cell, the protoplasm, plays an important part in the 

 excitability of the cell. Kiihne recognized the fact that the protoplasm 

 of Amoebae, Myxomycetes, and the filament hairs of Tradescantia, lost its 



1 Schultzen, Naunyn, and Munk: Du Bois' Arch. 1876, 340, and I. Munk: Pfliiger's 

 Arch. 12, 142 and 148 (1876). 



3 Baumann and Brieger: Z. physiol. Chem. 3, 254 (1879). 



3 Jaffe" and Hilbert: Z. physiol. Chem. 12, 295 (1888). Moraer: ibid. 13, 12 (1889). 



4 Schultzen and Naunyn: Du Bois' Arch. 1876, 353. 



5 Nencki: Arch, exper. Path. Pharm. 1, 420 (1873). 

 Nencki and Ziegler: Ber. 6, 749 (1872). 



' Jaff<5: Z. physiol. Chem. 2, 47 (1878-79). 



8 Cf. Fromm: Die chemischen Schutzmittel des Tierkorpers bei Vergiftungen. Strass- 

 burg, 1903. 



