LUPINES AS POISOISrOUS PLANTS. 29 



1914 the experiments were by forced feeding, so that the animal 

 received the total quantity in a short period of time; while in 1910 

 and 1911 some of the animals received large quantities, but the feed- 

 ing was distributed over a long period. Although in some cases as 

 much as 8 pounds was fed in a single day, this was eaten in a more 

 or less leisui'ely way. 



In 1912 two sheep, Nos. 175 and 168, were drenched with the fruit, 

 No. 175 receiving 1.435 pounds and No. 168 4.198 pounds, and 

 showed no symptoms, although the 1914 experiments indicated that 

 the toxic dose of fruit is about 1^ pounds. Sheep No. 175, however, 

 received its lupine in three doses, between 10.30 a. m. and 3.30 p. m.; 

 it is possible that this animal might have been poisoned had it re- 

 ceived the material in a single dose, as the quantity given was close 

 to the toxic limit. But sheep No„ 168 received 4.198 poim.ds, be- 

 tween two and three times the toxic dose as determined in 1914; 

 this material was given in six doses, between 8 a. m. and 7 p. m. It 

 seems probable that the only reason this animal was not poisoned 

 was because of the length of time during which the material was 

 given. 



It appears to be a fair inference that the excretory apparatus of 

 the sheep can take care of the toxic substance of the lupine provided 

 the quantity given at any one time does not reach the toxic limit. 

 It is hoped to carry on later detailed experiments to show just how 

 this is done — experiments for which adequate f acihties have not been 

 available thus far. It is probable, however, that this excretory work 

 is done largely by the kidneys, since preliminary experiments with 

 other toxic substances upon sheep indicate that the kidneys are 

 very efficient in the removal of some toxic substances. It has also 

 been shown by others that the lupine alkaloids are found in the 

 urine. The failure to get results in the earUer experiments was due 

 to the fact that the sheep did not get at any time more than the 

 excretory apparatus could remove before the toxic limit was reached. 



LUPINE NOT A CUMULATIVE POISON. 



The lupines as poisonous plants do not have a cumulative effect. 

 This has an important bearing on range management of sheep, for 

 it is evident that sheep may graze continuously on lupines with no 

 bad results, provided the toxic limit is not reached at any one time. 

 Inasmuch as the toxic dose is a fairly large quantity, and sheep do 

 not ordinarily show any special fondness for the lupines, well-fed 

 animals arc not likely to be poisoned by lupines. It is only when, 

 for some reason, th(;y cat an unusually large quantity that losses 

 occur. This is discussed in more detail under ''Ilange conditions 

 under which sheep are poisoned" on page 39. 



