30 BULLETIISr 405, U. S. DEPARTMENT OF AGEICULTUEE. 



TOXICITY OF DIFFERENT SPECIES OF LUPINE. 



The field experiments give little information as to any difference 

 in toxicity between the species of lupines. 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 poisoning was pro- 

 duced by L. myrianthus. 



The probable reasons why sheep were not poisoned on Lujnnus 

 Tnyrianthus 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. leucopJiyUus 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 alhus and L. angustifolius, are about 

 equally toxic with L. leucopsis and L. leucopJiyllus , 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, withX. leucopsis, andNos. 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 



