2J.\ TOXIC ACTION AND CHEMICAL COMPOSITION. 39 
Tropine C 8 H 14 N is structurally represented as CH 2 — CH — CH 2 
CH 2 NMe CH 
C 
h-ch 2 
and may be conveniently abbreviated in formulae to the letter T. 
Tropine is the parent member of the tropeines. No less than forty- 
five tropeines have been studied, and the effect of their dilute solutions 
on the cat’s eye examined and compared. The forty-five tropeines are 
divided conveniently into six groups :—- 
I. 
II. 
III. 
IV. 
Y. 
YI. 
Tropeines of aliphatic acids. 
,, of substituted benzoic acids. 
,, ,, hydratropic acids. 
,, ,, phenylacetic acids. 
,, ,, phenylpropionic acids. 
,, of acids in which the phenyl and carboxyl groups are 
separated by an imino group. 
I. Tropeines of aliphatic acids, such as acetyl-, lactyl-, terebyl-tropeine, 
in dilute solution are inactive. 
II. Tropeines of substituted benzoic acids, benzoyl-tropeine C 6 H 7 
C0 2 T, o-hydroxybenzoyl-tropeine H0C 6 H 4 C0 2 T, and the meta compound 
were active ; _p-hydroxybenzoyl-, protocatechoyl-, and phthaloyl-tropeine 
inactive. 
III. Tropeines of substituted hydratropic acids. To this group belong 
atropine, hyoscyamine, atroglyceryl-tropeine, atrolactyl-tropeine, all of 
which are active ; but atropine-sulphuric acid as well as atropyl-tropeine 
are inactive. 
IY. Tropeines of substituted phenylacetic acids. To this group belong 
the homatropines, the quaternary salts of homatropine, and 0 -, m-, and 
p-methylhomatropine ; these are all active. 
V. Tropeines of substituted phenylpropionic acids. Of this group 
/3-phenyl-a-hydroxypropionyl-tropeine CH 2 Ph.CH(0H)C0 2 T is a power¬ 
ful mydriatic for cats’ eyes, but when applied to the human eye is 
inferior to homatropine. 
YI. Tropeines of acids in which the phenyl and carboxyl groups are 
separated by an imino group. Hippuryl and phenyl carbamo-tropeine 
were examined ; the latter, Ph.NHC0 2 T, was found to be faintly active. 
It appears that the general results are that, for a tropeine to have a 
mydriatic action, a benzene nucleus is in most cases necessary ; that 
this is not essential is shown by the fact that /3-2-pyridyl-a-hydroxy- 
propionyl-tropeine, which contains a pyridine instead of a benzene 
nucleus, is active. The most active tropeines are those which contain an 
alcoholic hydroxyl group in the side chain containing the carboxyl group. 
