I 12 
platinum and gold are reduced already in the cold by anthranilic acid, 
also potassium permanganate; potassium chromate and bichromate, 
and salts of copper and silver, on the other hand, are not reduced 
even when the mixture is heated, the last-named salt not even when 
ammonia is added. If to an aqueous solution of anthranilic acid po- 
tassium ferricyanide and ferric chloride are added, a blue precipitate 
is formed. The sodium salt forms brownish-yellow laminae which are 
very readily soluble in water. In an aqueous solution, when potassium- 
bismuth iodide is added, a yellow-red precipitate is formed. 
Anthranilic acid is not apparently present in essential oils; but as 
derivatives of the acid are found in certain oils, it was necessary that 
a scientific investigation of these esters should be preceded by an 
examination of anthranilic acid itself. 
For the experiments on animals sodium anthranilate was always 
selected. 
Experiment No. i. A frog weighing 44 g (for all the experiments with 
anthranilic acid and its esters the eatable frog, Rana esculenta^ was employed) 
received 0,05 g sodium anthranilate dissolved in water. At the injection- 
spot the green and black pigment of the skin became almost immediately dis- 
coloured in a fairly sharply defined area of about i cm diameter; the skin 
assumed here a dirty yellow hue, which became tinged with red in consequence 
of the rapidly supervening hyperaemia. The passage of the sodium salt in the 
lymphatic vessel towards the zone of the pelvis was also marked by a slight 
discoloration of the pigment. In the course of the day the natural colours again 
became more pronounced, and after 24 hours the previously discoloured regions 
of the skin had again assumed their normal appearance. The same or corre- 
sponding symptoms after injection of sodium anthranilate, were subsequently 
not again observed, neither with the same frog, nor with others. For the rest, 
this dose of sodium salt had no apparent effect on the organism. 
Experiment No. 2. The same frog was given 0,2 g sodium anthrani- 
late. After 4 hours the animal felt very exhausted, and upon being stimulated 
mechanically, it crawled about slowly and with difficulty. The dorsal position 
was tolerated. After 5 hours, in the dorsal position, very shght tonic spasms, 
and slow irregular and inco-ordinated movements of the trunk, head, and extre- 
mities occurred. After 6 hours these inco-ordinated movements were only extre- 
mely feeble, the reflex-action scarcely noticeable. After 22 hours the animal 
was apparently dead, but by a small fenestra cut in the breast it was seen 
that the heart was still beating. After 44 hours the animal was found to 
be dead. 
Experiment No. 3. A frog weighing 60 g, was given 0,1 g sodium 
anthranilate. No consequent symptoms were observed. 
Experiment No. 4. A frog weighing 38 g received an injection of 
0,15 g sodium anthranilate. After 5 hours the animal reacted little when 
stimulated; inco-ordinated and tonic movements were indicated. After 10 hours 
it was no longer possible to obtain reflex. Death supervened after about 
40 hours. The section showed a medium degree of hyperaemia of the gastro- 
intestinal tract, and of the mesentery. The mucous membrane of the moulh 
was not affected by the hyperaemia. 
Experiment No. 5. 0,15 g sodium anthranilate was subcutaneously given 
to a frog weighing 45 g. After 3 hours the frog only made a few and futile 
efforts to change from the dorsal to the abdominal position. The movements 
