Derivatives of Tolidin. 489 
Leptoplastus occur in the lowest of the fine slates which 
succeeded to the flags and slate of Div. 2, and lithologically 
the beds fall into Division 3." 
In the Acadian area no trilobites are yet known in the 
great mass of sediments intermediate between the shales 
carrying Leptoplastus and those which hold Paradoxides, 
DERIVATIVES OF TOLIDIN. 
R. F. Rurran, B.A., M.D. 
In 1845 a Russian chemist named Zinin,’ by reducing 
Azobenzol with hydrogen sulphide obtained a substance 
which, when further treated with sulphuric aicd, gave rise to 
a base called Benzidin. The intermediate product of the 
reduction of azobenzol was subsequently examined by 
Hefmann’ and found to be Hydrazobenzol, and the nature 
of the reaction giving rise to Benzidin was made clear. 
From a homologue of hydrazobenzol, viz.: hydrazotoluol 
by Hofmann’s method, Petriew* prepared the homologue 
of Benzidin, viz., Tolidin, and studied some of its charac- 
teristics. The constitution of both Benzidin and Tolidin 
was afterwards established by Gustav Schultz.° These 
two bases were shown by him to be double molecules of 
anilin and toluidin, respectively, connected by their benzol 
neuclei, and having their amidogen groups in the para 
position. Their formulae being :— 
By (% H, NH, C; H, (CH;) NH, 
Benzidin + | | 
\c, H, NH, C, H, (CH,) NH, 
Benzidin has received some attention from chemists and 
many of its reactions have been investigated. Tolidin, on 
the other hand, owing to the difficulty with which it was 
otitin) 
‘In a former communication to this journal, they were referred 
to a8 probably at the top of Diy. 2. (See July, 1889.) 
* Journal fiir practische Chemie, xxxvi., 93. 
* Jahrsbuicht der Chemie, 1863, 424. 
* Berichte, vi., 557. 
* Liebig’s Annalen, 174, 227, Berichte, xvii., 467. 
