— 135 — 
The author therefore administered to himself 5,0 g piperonylic 
acid, and obtained from the urine two acids, of which one was the 
unchanged piperonylic acid, but the other piperonyluric acid 
Cg H3 (O2 CH2) C O N H C H2 . C O O H. This represents colourless, 
bright, broad prisms of the melting point 178°; in cold water it dis- 
solves with difficulty, but in hot water and in alcohol it is readily 
soluble. When boiled with hydrochloric acid it is split up into its 
components, of which one was recognised as piperonylic acid. 
Dr. Heffter adds in a note "As this and some other experiments 
showed, piperonal is physiologically quite free from action. The 
following particulars for which I am indebted to a medical friend 
show that it is also harmless to man. A chemist intending to commit 
suicide, swallowed 50 cc of a concentrated alcoholic solution of piperonal, 
i. e. about lOg. His health was in no way affected by it." 
Now a chemical substance may undoubtedly be almost completely 
indifferent in the animal body, and need not show, even in large 
doses, a toxic effect, or one of pharmaco-dynamic value. The chemical 
changes which take place in the organism may be very slight, and may 
qualitatively and quantitatively be so little beyond the normal, that 
functional disturbances do not occur at all. On the other hand, every 
animal reacts upon a poison in a varying degree, and in a different 
manner, according to its chemical organisation. In dogs and rabbits 
I could certainly not observe any subsequent symptoms, even with 
doses of 5,0 or 4,0 g respectively. 8,0 g piperonal administered to a 
medium-sized dog per os caused severe stomach complaints, so that 
after i ^j^ hours the animal began to vomit with severe vomiturition, 
in consequence of which probably almost the whole of the administered 
substance was ejected from the stomach. 
But the experiments made with frogs showed surprising results. 
Experiment No. i. Two frogs weighing 30 and 31 g respectively, received 
each an injection into the lymphatic vessels of the back, of 0,08 g piperonal 
in emulsion with acacia. Paralysis occurred almost immediately ; the anterior 
extremities responded little to mechanical stimulation, whilst the reflex-action 
of the posterior extremities had ceased. Respiration and pulsation became 
more feeble, and ceased after half an hour. The section showed, that the 
emulsion was completely resorbed. Muscles and nerves reacted normally on 
electric stimulation. The disappearance of the reflex-action must therefore have 
been due to paralysis of the central nervous system , whilst many substances 
of the group of essential oils exert an action which paralyses the nerves peri- 
pherally, in the manner of curare. 
Experiment No. 2. Two frogs weighing 30 and 32 g, each received 0,04 g 
piperonal in acacia- emulsion. After a few minutes paralysis occurred already, 
so that the dorsal position was tolerated. After 24 hours the animals had 
completely recovered. 
An mjection of 0,05 g piperonal showed the same symptoms. 
Experiment No. 3. Two frogs received 0,075 g piperonal each, in emul- 
sion. Again paralysis of the extremities supervened very rapidly; the reflex-action 
