The number of plants containing volatile oils is enormous, and the 
variety of purposes for which these plants and their oils have 
been employed medicinally from time immemorial, in the most diverse 
countries, is also not inconsiderable. It should be the object of scientific 
pharmacology to ascertain to which constituents of the essential oils 
(which are mostly of very mixed compositions) the particular effects 
must be attributed. This question can only be solved in one way, 
and that a very difficult one; that is to say, by decomposing the oils 
into their constituents, and by testing each individual constituent for 
its physiologico-chemical and pharmacological behaviour. The decompo- 
sition of the oils is a subject to which a few individual chemists have 
applied themselves for many years, notably among them Wallach, 
and also Messrs. Schimmel & Co.; but the examination of the action 
of the constituents isolated from those oils is a long way behind. May 
the following pages form a small contribution towards the solution of 
this task. 
I am indebted to the kindness of Professor Rudolf Kobert for 
having had placed at my disposal anthranilic acid and a few of its 
esters, and further piperonal, for the examination of their pharmaco- 
logical properties, and of the fate of these bodies in the animal organism. 
With the exception of piperonal, I have found in the literature on 
the subject no particulars on the physiologico-chemical and pharmaco- 
logical behaviour of these substances. 
Anthranilic acid and some of its esters. 
Anthranilic acid 
/NH^ (i) 
' ' ' ' '\C00H(2) 
is orthoamido benzoic acid. Its melting point lies at 144° to 145°. 
The acid, which can be sublimed, is on distillation split up into aniline 
and COg. In water and alcohol it is readily soluble; the aqueous 
solution shows a blue opalescence, and has a slightly sweet taste. 
Anthranilic acid crystallises in leaflets or trimetrical crystals. Salts of 
