30 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. 
TOXICITY OF DIFFERENT SPECIES OF LUPINE. 
The field experiments give little information as to any difference 
in toxicity between the species of lupmes. While only one of the 
two species used in the experiments with horses produced effects, viz, 
Lupinus myrianthus, the feedings of L. comatus were not conducted | 
under exactly the same conditions, the period of feeding being con- 
siderably longer than in the experiments in which sane was pro- 
duced by L. myrianthus. 
The probable reasons why sheep were not aeiabaca on Lupinus 
myrianthus and L. comatus are discussed on page 28. Nearly all the 
experiments at Greycliff were on L. leucopsis. The field experi- 
ments on L. argenteus and L. leucophyllus were so few that it is not 
safe to make any deductions. It seems probable that in the experi- 
ments of feeding the seed of L. argenteus, the dosage was just a little 
too small, even granted that the plant is equally toxic with L. 
leucopsis. 
The experiments with mice detailed on pages 25 to 28 indicate that 
the European species, Lupinus albus and L. angustifolius, are about 
equally toxic with L. leucopsis and L. leucophyllus, while L. luteus is 
much less toxic, the dosage probably being at least three times as 
great as that for the other species. Inasmuch as the experiments 
on mice were few in number, too much importance must not be at- 
tached to the results. They are interesting, however, as giving some 
indication of the probable comparative toxicity of the species ex- 
amined. These experiments with mice give an indication of the 
probable toxicity of the leaves as compared with other parts of the 
plants. 
TOXICITY OF LUPINE LEAVES FOR SHEEP. 
Sheep No. 243 was an undoubted case of lupine poisoning. The 
symptoms were typical and it received only leaves. It was impos- 
sible, however, to verify this by other experiments. The other ani- 
mals (Nos. 295, 266, 256, 290, and 306, with L. leucopsis, and Nos. 263 
and 307 with L. argenteus) were fed much more, in some cases more 
than three times as much, without any effect whatever. It should 
be added that while all animals upon the range apparently graze 
upon lupine with impunity, sometimes eating very large quantities, 
there are cases when it seems probable that lupine leaves must be 
toxic. For example, cases of undoubted lupine poisoning in the 
Absaroka National Forest, examined by Dr. Hadleigh Marsh in the 
summer of 1914, apparently did not have an opportunity to obtain 
enough of the seeds to cause the difficulty. If it could be assumed 
that the leaves are sometimes toxic, these cases would be much more 
easily explained. Many similar cases of range poisoning have oc- 
curred where it was difficult to explain the loss except by assuming 
