780 EXPERIMENT STATION BECORD. [Vol.35 



of Delphiniums, the losses from larkspur poisoning, common names of lark- 

 spurs, species concerned in poisoning, and the detection of species in the 

 stomach contents. Part 2 (pp. 28-59) presents the details of experimental 

 work, and part 3 (pp. 59-84) is devoted to a discussion of the results obtained 

 and the conclusions drawn. 



The authors find that " it is rarely possible to recognize macroscopically 

 larkspur material in the stomach contents of cattle. By means of microscopic 

 sections of stems, however, not only can Delphinium be distinguished from 

 other plants but groups of the genus can be distinguished from each other. 

 The genus falls into six different types of stem structure. 



" Experimental feeding of larkspur was carried on for three seasons at 

 Mount Carbon, in Gunnison County, Colo. In this work four species of Del- 

 phinium were used which have been identified as Delphinium barbeyi, D. 

 menziesii, D. andersonii, and D. robusUim. A large number of animals was 

 used in this work, including horses, cattle, and sheep. Similar feeding ex- 

 periments were conducted during one season at Greycliff, Mont., on D. cucul- 

 latum and D. bicolor. These experiments showed that the larkspurs are 

 poisonous to cattle and horses but not to sheep. Horses, however, in pastures 

 or upon the range do not eat enough of the plants to produce any ill effects, 

 so that losses of stock from larkspur poisoning are confined to cattle. 



" The low larkspurs are poisonous during the whole life of the plants, but 

 inasmuch as they disappear early in July, cases of poisoning are confined to the 

 months of May and June. The tall larkspurs live through the summer season, 

 appearing in early spring. They are most poisonous in their early stages. 

 After blossoming the toxicity gradually diminishes and disappears and the plant 

 dries up, although the seeds are very toxic. Most of the cases of poisoning in 

 Colorado occur in May and June, with sporadic cases in July. In other locali- 

 ties where the larkspurs blossom later poisoning may occur as late as August 

 or even September. 



" While definite feeding experiments have been performed upon only a few 

 species of larkspur, it may be assumed, from the knowledge of plant poisoning 

 upon the ranges, that other species have the same properties as those experi- 

 mented upon and that feeding upon them produces the same results. The 

 experimental work and the autopsies showed a clearly defined line of symptoms 

 and certain definite pathological results. The feeding showed that there was 

 no marked difference in toxicity between the different species of larkspurs and 

 that the quantity necessary to produce effects varied within rather wide limits, 

 but that, generally speaking, a quantity equal to at least 3 per cent of the 

 weight of the animal was necessary to produce poisoning. 



" From somewhat extensive experimental work on antidotes it was found 

 that beneficial results could be obtained by using, hypodermically, injections of 

 physostigmin salicylate, pilocarpin hydrochlorid, and strychnin sulphate, fol- 

 lowed by hypodermic injections of whisky when needed. 



" Poisoning upon the range may be prevented in some cases by digging up 

 the tall larkspur when the greater number of plants is confined to compara- 

 tively limited areas. In other cases the handling of the cattle in such a way 

 that they will not have an opportunity to feed upon the larkspur may prevent 

 losses. In the case of D. menziesii it is desirable that the cattle should be kept 

 away from the ranges where this plant grows in abundance until about the first 

 of July, when the plant dies. D. barbeyi loses Its toxicity after blo.ssoming, so 

 that a range with this plant is safe for cattle in the late summer and fall. It 

 should be remembered, however, that local and climatic conditions may delay 

 the time of blossoming, so that no arbitrary date can be given when a range is 

 safe. D. bicolor probably never grows in sufllcient quantities to be dangerous 



