WESTERN SNEEZEWEED AS A POISONOUS PLANT. 37 



If Table 13 is taken at its face value, we must consider the plant 

 as most toxic in midsummer and more toxic in September than in 

 June. 



It may be seen from Table 1 that in 1918 four sheep were poisoned 

 by feeding in June and July, while only one sheep, No. 469, was 

 poisoned by feeding late in the season; this from August 26 to Sep- 

 tember 19 received 36.058 pounds — an average daily feeding during 

 25 days of 1.442 pounds. In these cases, again, the dosage of the 

 latter part of the season was rather smaller than it was earlier. 



While the numbers of cases in different parts of the year are too 

 small to permit of reliable averages, it seems that there is an apparent 

 tendency to slightly greater toxicity in the latter part of the season. 

 This probably is explained by the greater quantity of water con- 

 tained by the plant early in the season. In general, it may be stated 

 that there is no marked seasonal variation in toxicity. 



PERMANENT EFFECT PRODUCED BY THE POISON. 



It was noticed in the corral cases that the effect of H. hoopesii poi- 

 son was continued for a prolonged period, and that complete recov- 

 ery, if it occurred at all, was slow in appearing. People who handle 

 sheep in the H. hoopesii region have a theory that a spewing sheep 

 never completely recovers. It is stated that if a band of sheep is 

 brought from the outside to a H. hoopesii range, there are compar- 

 atively few cases the first year, more the second, and still more the 

 third. This is explained by supposing that the effects of H. hoopesii 

 feeding continue over from year to year. In connection with the 

 experiments at the Salina station, some sheep were kept for two or 

 more years and notes made in regard to the outcome of cases that 

 were poisoned and apparently recovered. The results appear to 

 show quite conclusively that the effect of H. hoopesii poison may be 

 permanent; that sheep once affected by this plant are likely to suc- 

 cumb more quickly to a succeeding feeding, and, even if they appar- 

 ently recover, are likely to prove worthless. 



Helenium hoopesh a Cumulative Poison. 



As previously shown, if about 2 pounds of H. hoopesii leaves are 

 fed daily for- about 20 days, sickness is produced, although a consider- 

 ably smaller amount may have a toxic effect. For instance, in 1918 

 Sheep 469 was made sick on a daily feeding of 1.6 pounds, while on 

 the other hand 1.5 pounds was fed daily for more than 20 days with- 

 out producing any effect. If less, however, than 1.5 pounds a day 

 is fed, positive symptoms do not develop. For example, Sheep 467 

 ate on the average of 1.3 pounds a day for 40 days without showing 

 any distinctive symptoms. It will be remembered also that a single 

 day's forced feeding of 2.494 pounds produced toxic symptoms. 



