244 INTESTINAL BACTERIA 
They are united with sulphuric acid in the liver to form ethereal sul- 
phate. 
~ OH H—O O O 
OS (aX 
: H—o”  o | o%” o 
Ww 
This is usually excreted as a sodium or potassium salt. 
Putrefaction of Tryptophan. Hopkins and Cole have determined 
the steps in the decomposition of tryptophan by cells. 
0 0 
( \6--CHe—cH—-CL0H =) —C—CHe-CHsA C—O 
| | 
| | oC NHo2 | | C 
V7 AVF 
i i 
H H 
Tryptophan Indol propionic acid 
(-\—C—CH—Ci (\—C-Clt ( \—¢-H 
aa | f Cc —i| fc 
VAL LAS A/S 
{ i i 
N H H 
Indol acetié acid Methyl indol (skatol) Indol 
The final product is methyl indol or skatol. For excretion this may be 
united with sulphuric acid as follows: 
O 
(S—C—CHs ( \—C—CH,OH ( \—C—CH.—0s€ 
| | | o” ro 
AP AR AA 
f WAN AN K 
I _— L 
H H H 
Indol is prepared for excretion in the same way. 
Putrefaction of Arginin. Putrecin in the end product and was 
supposed to be important in certain types of food poisoning. It is 
formed from arginin as follows: 
