1013 
Experiment A.—Guinea pig of 210 grams: 1 cubic centimeter of crude extract, 
containing 0.01 gram of alkaloid, injected intraperitoneally. After four minutes 
the animal begins to tremble and apparently to lose control of the muscles sup- 
porting the head; after seven minutes it lies down, unable to move, after which 
several spasmodic respiratory movements follow. Dead in fifteen minutes. 
Experiment B.—Guinea pig of 195 grams: 0.5 cubic centimeter of crude extract, 
containing 0.005 gram of alkaloid, given intraperitoneally; all the usual symptoms 
of asphyxiation follow, but the animal lives for forty-eight hours. 
The physiological tests on pure echitamine hydrochloride which are 
reported below, show that the minimum fatal dose for a guinea pig of 
about 200 grams is 5 milligrams and that 0.01 gram kills an animal of 
this size in about sixteen minutes, the symptoms being exactly the same 
as those observed with the crude extract. Hence, I consider that 
Experiments A and B prove that practically all the physiologically active 
constituent of the bark has been extracted, and that this substance is 
the alkaloid echitamine. 
THE ALKALOIDS OBTAINED FROM DITA BARK. 
Ditamine.—Hesse * has given this name to the alkaloid which can 
be obtained by rendering the aqueous solution from the plant alkaline 
with sodium carbonate, and then shaking out with ether. The alkaloid 
is removed from the solvent by means of dilute acetic acid, which is 
then rendered alkaline with ammonia and the resulting solution extracted 
with ether. Hesse states the yield of this alkaloid to be 0.02 to 0.04 per 
cent, but from 10 kilos of the bark he obtained only 0.4 gram of 
ditamine ; the other nine tenths of the alkaloid he believes to have been 
occluded by one of the resins. I have succeeded in obtaining only very 
small amounts of ditamine, the largest yield being 0.3 gram of alkaloid 
from 5 kilos of bark. I have not been able to separate ditamine from 
any of the resins. ‘These facts, together with my physiological experi- 
ments on the crude extracts from the plant, and Harnack’s repeated 
claims that the dita bark contains but one alkaloid, make it doubtful 
whether the bark contains the percentage of ditamine claimed by Hesse. 
As deposited from ether, ditamine is a varnish-like substance, slightly yellow- 
ish in color. It is easily soluble in ether, benzene, chloroform, and alcohol. 
From all these solvents it separates in an amorphous condition. It is not very 
soluble in petroleum ether. Some ditamine was dissolved in a small volume of 
chloroform and to this three volumes of petroleum ether was added. The ditamine 
separates at once in flocks, but is not obtained in a crystalline form by this 
procedure, Solutions of ditamine in the solvents mentioned above were very 
slowly allowed to evaporate for some weeks in the cold storage, but no crystals 
were obtained. 
Concentrated sulphuric acid dissolves ditamine, giving a red color, which on 
warming becomes more violet, but the color is not nearly as strong as in the similar 
test with echitamine. With concentrated nitric acid a blue, then a green color is 
22 Loe. cit. 
