74 
Vet. XXIII, No. 2 
Journal of Agricultural Research 
With known weights of the raw alkaloids from definite quantities of 
the three samples, the way was now open for comparative tests of their 
toxicity. To this end all three total alkaloidal residues were dissolved 
in exactly 5 cc. of very dilute acetic acid, and 0.5 cc. of each was injected 
subcutaneously into three mice. The result was the same in each instance 
the animal died almost instantly in violent convulsions. The dosage 
was as follows: 
B. cucullaria: 
Tops.0.5 gm. plant==o.0062 gm. alkaloid. 
Roots.0.5 gm. plant= .0080 gm. alkaloid. 
B. canadensis: 
Roots.0.5 gm. plant= .0157 gm. alkaloid. 
By testing these solutions at gradually increasing dilutions it was 
possible to determine within narrow limits the minimal fatal dose of the 
three with respect to mice of about 20-gm. weight, as shown in Table III. 
Table III.— Minimal fatal dose of Bikukulla cucullaria and B. canadensis for mice of 
20 ~gm. weight 
Plant. 
Weight 
of 
plant. 
Alkaloid. 
Total dose 
per kilo¬ 
gram of 
body 
weight. 
B. cucullaria: 
Gm. 
Gm. 
Gm. 
Tops. 
0. 040 
O. 0005 
O. 02 
Roots. 
.031 
.0005 
. 02 
B. canadensis: 
Roots. 
. 250 
. OIOO 
.40 
From these figures it can be estimated that the combined alkaloids of 
Bikukulla cucullaria roots and those of the tops are of approproximately 
the same degree of toxicity. 
This finding runs counter to observations made in the field tests on 
calves, as reported elsewhere, in which 60 pounds of the tops were fed 
without effect. A possible explanation of this result is that the bulk and 
succulence of the fresh tops so dilutes the poison that its action is mini¬ 
mized and it is absorbed so gradually that the animal suffers no ill effects. 
Nevertheless the fact remains that the tops contain the poison and must 
be held partially accountable for the poisoning of grazing stock which eat 
the whole plant. Applying the foregoing figures to a comparison of the 
relative toxicity of the roots of Bikukulla cucullaria and B. canadensis, 
it will be seen that the alkaloids of B. cucullaria are about 20 times as 
poisonous as those of B. canadensis, but as there is a considerably larger 
percentage of alkaloids in B. canadensis the ratio of toxicity between the 
two plants would be reduced to approproximately 6 to 1. 
As a preliminary experiment to acquire some information about the 
character of the alkaloids in the two plants under investigation, 100 gm. 
of each were extracted in a Sohxlet apparatus with the selective solvents, 
ether, chloroform, alcohol, and acidified water. In the case of Bikukulla 
cucullaria the acidified water gave only the faintest of tests with Mayer’s 
reagent, showing that the other three solvents had made a complete 
extraction. All three solutions contained appreciable quantities of 
alkaloids. From the chloroform and alcohol fractions only amorphous 
