a46 MANUAL OF POISONOUS PLANTS 



vated extensively in India. The Durras have been cultivated for centuries in 

 Egypt, and other countries of Africa, and in India for human and animal food. 

 They are now cultivated in the United States, chiefly from Kansas to Texas. 

 The Kaffir, native to eastern Africa from Abyssinia to Natal, was introduced 

 into this country in 1875, and is grown chiefly in the semi-arid regions for 

 forage. Sorghum is grown largely for fodder. The pithy juice contains cane 

 sugar in variable amounts, and is used both for sugar and in the making of 

 syrup, although the growing of sorghum for syrup seems to be on the decline. 

 According to the census of 1890 the production was 24,000,000 gallons; in 1900, 

 17,000,000. 



Poisonous properties. Sorghum has long been recognized as poisonous. 

 Mr. C. W. Warburton in Bailey's Encyclopedia of Agriculture, says: 



Sorghum makes excellent pasture for hogs, but in many sections it must be pastured 

 sparingly, if at all, by sheep and cattle. After periods of extreme drought, or when growth 

 is stunted from other causes, the leaves of the sorghums often contain a large amount 

 of prussJc acid. A small quantity of this poison is fatal to stock, and death frequently 

 results soon after the sorghum is eaten. Normal growth seldom contains prussic acid in 

 appreciable quantities, and it largely disappears in curing, so that cured sorghum may be 

 fed with little danger. There is also some danger from bloating; cattle and sheep should 

 not be turned on sorghum pasture when hungry or when the plants are wet. With the 

 exercise of care, however, the crop can usually be pastured with safety. It should be 

 at least two feet high before stock are turned on it; for cattle, sheep and horses it 

 may be much more matured than for hogs 



Frosted cane is said to be especially injurious. Dr. R. H. True, of the 

 U. S. Dept. of Agriculture, in commenting on the poisons from sorghum, says: 



This office has from time to time received communications from stockmen, especially 

 in the lower part of California, Arizona, and adjacent territory, expressing a suspicion 

 that the eating of the Johnson grass had caused the death of stock with rather sudden and 

 violent symptoms. There has seemed to be little ground in poisonous-plant literature to 

 support such an explanation. Last summer, however, convincing observations were reported 

 from California by a stockman who had lost heavily, and a supply of the grass in question 

 was obtained. The result of the study of this material was positive. 



Mr. A. C. Crawford, who investigated some cases, says: 



It has been noted that deaths in cattle frequently occur when, on account of the failure 

 of rain, the plants which have reached a certain size become stunted and withered. The 

 toxic principle appears simultaneously over a wide area, but soon disappears if a rainfall 

 occurs. The deaths of cattle have been attributed by some to an insect living upon the 

 plant, and in Australia it is the belief thatSorghvm vulgare which also yields hydrocyanic 

 acid, becomes more poisonous when attacked by an insect during a drought. A similar 

 observation has been made with Sorghum vulgare in the Sudan. Balfour found that one 

 specimen of the plant which harbored aphids yielded more hydrocyanic acid than a second 

 one without parasites. Pease has lately claimed that the deaths from Johnson grass in 

 India were really cases of nitrate poisoning, as he found 25 per cent of nitrate of 

 potassium in the stem of the plant and was able to produce somewhat similar symptoms in 

 animals by feeding them this salt. Johnson grass is being introduced into Australia as 

 a fodder plant, but as yet no reports of its poisonous action there have been noted by 

 the writer. 



Dr. George H. Glover of Colorado, also reports large loss of cattle in that 

 state from eating Kaffir corn. Twenty-one head out of thirty-two cows died 

 within an hour after first being placed upon the feed. Dr. A. T. Peters of 

 Nebraska, investigated the subject of poisoning from sorghum and Kaffir corn. 

 He states that in most cases where death of animals occurred, the animals 

 did not regularly pasture upon sorghum, but broke into the fields from ad- 

 jacent pastures or as they were being driven past fields of sorghum. The 

 investigations proved that the animals did not die from bloat as had been re- 



