42 BULLETIN 405^ U. S. DEPAETMENT OF AGRICULTURE. 



occur at the time when the plants are m fruit and in seasons when 

 the fruit is most abundant. In very dry seasons frequently little 

 fruit is matured, while a wet season, especially a wet spring, may 

 cause a heavy production of fruit. 



SUMMARY. 



(1) Lupines have been cultivated and used from the tune of the 

 ancient Greeks and Romans, but their poisonous properties have been 

 recognized only in very modern times. Heavy losses of domestic 

 animals were reported in northern Germany in 1872 and the suc- 

 ceeding years. 



(2) While chemists have shown the presence of poisonous alkaloids 

 in the lupines, the losses in northern Germany have been considered 

 by investigators as due not to the alkaloids but to a hypothetical 

 substance known as ictrogen. 



(3) An investigation by Dr. Sollmann showed the presence of 

 alkaloids in American lupines, and pointed to the probability that 

 most, if not all, the poisoning of hve stock in America was due to 

 these alkaloids and not to ictrogen. 



(4) Extended field work has verified the conclusions of Sollmann 

 and has shown that all aerial parts of the lupines examined are 

 poisonous, the seeds being the most toxic, then in order the pods and 

 leaves. This has been confirmed by preliminary experiments with 

 extracts upon mice. 



(5) The toxic substance is excreted by the kidneys; the intoxica- 

 tion is not cumulative, and animals may eat comparatively large 

 quantities with no iU results, if the toxic limit is not reached at any 

 one time. Inasmuch as the toxic and lethal limits are nearly the 

 same, the prognosis for poisoned animals is not favorable. 



(6) There is no form of remedial treatment that can be used ad- 

 vantageously for range animals. Poisoning in most cases can be 

 avoided, even where the plant is abundant, by careful handling of 

 the flocks, especial care being taken to see that hungry sheep are 

 not grazed on fields where there is much lupine. 



