10 BULLETIN 1240. U. S. DEPARTMENT OF AGRICULTURE, 
affected the epithelium of the convoluted tubules, the ascending limb 
of Henle, and the capsule of Bowman. 
The liver was much less affected. There was a mild, cloudy swelling 
of the hepatic cells, with beginning granular degeneration in the 
cytoplasm bordering on the capillaries. The bile ducts were usually 
catarrhal and sometimes an infiltration of round cells had occurred. 
The condition of the bile ducts was probably not caused by the Zyga- 
denus. 
The principal effect on the lungs was a mild capillary congestion. 
In the more congested areas there was a considerable quantitv of 
yellowish, granular pigment, such as is derived from the degeneration 
of red blood corpuscles. This was largely lying free in "the tissue 
spaces. There was also a mild catarrhal condition of the small 
bronchial tubes and the bronchioles. 
The tissues most affected were the epithelial cells of the convoluted 
tubules, ascending limb of Henle, and capsule of Bowman in the 
kidneys, and to a less degree the hepatic cells and bile duct epithelium 
of the liver. 
As tissues from only a single animal were studied, too great im- 
portance should not be attached to the findings. The conditions,, 
however, seem to suggest that the toxin was mainly excreted by the 
kidneys, and that the liver played a less important part in eliminating 
the poison. 
The results of microscopic studies on the tissues of a number of 
animals fatally poisoned by other species of Zygadenus correspond 
to the findings recorded for this case. 
TOXICITY OF PLANT AND SUSCEPTIBILITY OF ANIMALS. 
TOXIC AND LETHAL DOSAGE. 
Sheep. — An examination of Table 1 shows that the minimum toxic 
dose of the force-fed sheep was 0.3 pound per 100 pounds of animal, 
in the case of sheep 541. This animal showed only symptoms. It 
should be noted that sheep 603 exhibited only symptoms on 1.047 
pounds per 100 pounds of animal, a quantity more than three times as 
great as that received by sheep 541. The severity of the effect of the 
plant was indicated in the table by the terms ''symptoms." ''sick.'' 
and "very sick. ; ' Of the "sick" sheep the minimum dose was that 
of sheep (342, namely, 0.5 pound; the same sheep in another experi- 
ment received 1.6 pounds with a similar effect. The minimum dose 
making the animal ''very sick" was 1.7 pounds in sheep 617 and the 
maximum 1.8 pounds in sheep 639. 
It will thus be seen that there is considerable latitude in the toxic 
dosage, for while a sheep was poisoned on 0.3 pound, sheep 643 on 
July 7 received 0.718 pound with no effect. 
The only animal killed was sheep 637, which received 2 pounds per 
100 pounds of animal. This is probably very close to the minimum 
lethal dose, for of the other force-fed cases not resulting in death, 
sheep 642 received 1.6 pounds; sheep 612, 1.7 pounds; sheep 617. 
1.7 pounds; and sheep 639, 1.8 pounds. It may be noted that Flem- 
ing and coauthors (1921, p. 17) report a case of death of a sheep on 2 
pounds of this plant. 
Cattle. — Only 2 head of cattle were poisoned, and the minimum dose 
w.'.s 0.838 pound per 100 pounds of animal, in No. 900, while No. 903 
