544 MANUAL OF POISONOUS PLANTS 



from 1/2-1/3 of an inch wide, edge of the leaf entire or somewhat wavy and 

 hairy; stipules united and decurrent on the stem, inversely arrow shaped; 

 peduncles few-flowered ; flowers yellow, about % of an inch in diameter ; calyx 

 5-cleft, standard of the flower large, heart-shaped; keel scythe-shaped; stamens 

 monadelphous, anthers of 2 sizes, 5 smaller and roundish ; pod large, inflated, 

 bears a close resemblance to the garden pea, greenish at first, becoming black- 

 ish; seeds from 1/10-1/12 of an inch in diameter, flattish, kidney-shaped, which, 

 when mature, break away from the point of attachment and rattle in the pod, 

 hence the name "rattle-box." 



Distribution. This plant is common in sandy soil from Maine to Minnesota, 

 South Dakota, Iowa, Nebraska, and Northern Texas. The plant is extremely 

 common on the sandbars of the Missouri river, where it may be collected by the 

 wagon load. 



Poisonous nature. The earliest mention of the poisonous nature of the 

 weed was made by Drs. Stalker and Bessey. Dr. Stalker who performed some 

 experiments with the plant gives the following symptoms : 



The disease had been known in this region for three or four years, but had not until 

 the present summer (1884) prevailed to such an extent as to attract generally public at- 

 tention. But now the loss in horse stock on some farms was not to be counted by hundreds, 

 but by thousands of dollars. The disease proved to be one that had not hitherto come 

 within the range of my experience, nor had I any information of anything exactly identical 

 with it. I spent several days among the farmers on the Iowa side of the Missouri river, 

 taking careful notes of the symptoms, and gathering the history of the progress of the 

 disease. On some farms I found almost all the horses affected, and on others but a few 

 individuals. Deaths were an almost daily occurrence, and the farmer who owned a large 

 stock of horses did not know today whether he would have teams for his farm work a week 

 later. The disease in most cases is very slow in its progress, but proving almost uniformly 

 fatal after a number of weeks or months. There is a general decline of bodily vigor 

 throughout this period, and the only abnormal symptom in many cases is that of marked 

 emaciation and consequent weakness. Horses that have been kept at pasture through the 

 summer, without work, and where the grass grew in greatest abundance, were so thin in 

 flesh that they walked with the greatest difficulty. A critical examination of many of 

 these patients revealed nothing more than the condition resulting from starvation. This 

 was not uniformly the case. In a number of instances there was marked, coma or stupor, 

 the animal often falling asleep while eating. In some instances the animal would remain 

 standing for a whole week, sleeping much of the time with head resting against some 

 object. In a few instances the animal lost consciousness, and broke through fences and 

 other obstructions. A number of the diseased animals were placed at my disposal, and 

 assisted by Dr. Fairchild and Dr. Milnes, I made post mortem examinations of five sub- 

 jects with the most perfect uniformity as to the lesions presented. In every instance there 

 were marked haemorrhagic effusions into the fourth ventricle, the liver and spleen were 

 abnormally dense, the walls of the intestines were almost destitute of blood, and the 

 stomach enormously distended with undigested food. The stomach with its contents in 

 some instances weighed as much as seventy pounds. These post mortem conditions, to- 

 gether with clinical symptoms, led me to believe the animals were obtaining some poisonous 

 principle with their food. The symptoms in some cases bore such a resemblance to those 

 produced by eating Astragalus mollissiinus, or "loco plant" of the Western plains, as to 

 direct my investigations to that family of plants. A careful examination of the meadow 

 and pasture lands was not rewarded by the discovery of a single "loco plant." 



It took but little investigation, however, to find a closely related plant growing in 

 great abundance, both in the meadows and pastures. This was the Crotalaria sagittalis, or 

 rattle-box. This is also known as the wild pea, and is accounted by many farmers as the 

 best of forage plants. Knowing the bad reputation of some of its near relatives, I de- 

 termined to make s<3me experimental tests with the plant. I employed a boy to collect 

 about thirty pounds of the green plants, which I brought with me on my return to the 

 college. I procured a strong young horse, affected with incurable catarrh, and attempted 

 to induce him to eat the plant. This he persistently refused to do, though I sharpened 



