49 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. 
occur at the time when the plants are in 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 time 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 live 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 ill 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. 
