28 BULLETIN 405, U. S. DEPARTMENT OF AGEICULTUEE. 



may be noted in passing that L. luteus is the species which is said to 

 be responsible for the so-called ictrogenic poisoning which occurs in 

 northern Germany. In regard to the American species, L. leucopsis 

 and L. leucopTiyllus are about equally toxic and do not differ much 

 from L. albus and L. angustifolius. L. argenteus appears to be much 

 more toxic than the other American species examined. 



It should be noted that in these experiments on mice the animals 

 died of respiratory paralysis, with marked dyspnoea, the heart some- 

 times continuing to beat as much as a minute after respiration had 

 ceased. The work with extracts is of a preliminary character, and 

 it is intended to prepare for future pubhcation an extended study of 

 the alkaloids and the effect of the extracts. 



PART III.— DISCUSSION AND GENERAL CONCLUSIONS. 

 Failure to poison sheep in 1910, 1911, and 1912. 



In the early work of the field experiments it was assumed that the 

 lupines were sufficiently toxic to poison animals in the course of ordi- 

 nary feeding. It was thought that if the animals were confined and 

 given httle or nothing of other food material and were abundantly 

 supphed with lupine, symptons would appear if the plants were toxic. 



There was httle in American hterature to indicate the probable 

 dosage. Chesnut and Wilcox (1901, p. 108) state that 150 pods were 

 fed to each of two sheep and both were fatally poisoned. Accord- 

 ingly, in 1910 the sheep used were confined in corrals and were fed all 

 they would eat. One animal, sheep No. 102, between July 6 and 30, 

 ate 128 pounds of lupine tops, including leaves, flowers, and fruit, and 

 another, between August 25 and September 7, ate 55.5 pounds of 

 seed-containing pods, with no iU effects other than a loss of weight. 

 Sheep No. 105, which received the 55.5 pounds of pods and seeds, was 

 given on some days as much as 8 pounds. 



The experience of 1911 was similar and with no more results. 

 Although a large number of experiments were made in 1912, in only 

 one case were there harmful results. This animal, sheep No. 180, 

 was fed 0.85 pound of lupine seeds on September 15, and the next 

 day it was found dead in the pasture. At that time, because of the 

 large number of negative experiments, it was thought that the death 

 of the animal must be due to some other cause than lupine poisoning. 

 The more complete knowledge of the effect of lupine, brought out in 

 the work of 1913 and 1914, makes it evident that this was a case of 

 lupine poisoning. AU the other cases of 1912 were negative. 



In comparing the work of these years it will be noticed that in 

 1913 the feeding of seeds was done in a single day, and in most cases 

 the quantity fed was eaten in a short time. This was true of sheep 

 No. 180 in 1912, which ate the given quantity within an hour. In 



