POISONOUS ACTION OF JOHNSON GRASS. 33 



second one without parasites. Pease has lately claimed that the 

 deaths from Johnson grass in India were really cases of nitrate poison- 

 ing, 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. a 



There has been some chemical study of Johnson grass, but not with 

 reference to any poisonous principle. 6 



A fresh, green, mature, nonflowering specimen of Johnson grass, 

 moistened with a little water and preserved with chloroform, was sent 

 from Santa Rosa, Cal., in sealed glass vessels, to this laboratory. 

 This was botanically identified here as Johnson grass. This specimen 

 was not immediately worked up, but remained in the jars for about a 

 month. At that time on opening the jars a marked odor of hydro- 

 cyanic acid, together with that of chloroform, was detected. The 

 ground-up plant, with the water in which it came, was distilled, and 

 the distillate was caught in sodium hydrate solution. This distillate, 

 on mixing with ferrous sulphate and acidulation with hydrochloric 

 acid, gave a heavy blue precipitate with ferric chlorid. Yellow ammo- 

 nium sulphid was added to the same nitrate, and the mixture was 

 evaporated to dryness on the bath. The dried residue was then taken 

 in hydrochloric acid water, and on the addition of ferric chlorid the 

 fluid gave the characteristic red reaction for hydrocyanic acid. The 

 nitro-prussid, picric acid, and silver nitrate reactions were all positive 

 for hydrocyanic acid. The aqueous fluid in which the plant was 

 shipped was filtered off from the plant and gave on distillation all the 

 above reactions for hydrocyanic acid. 



According to our California correspondent, this plant is poisonous 

 when grown on irrigated as well as on nonirrigated lands, but especially 

 so when grown on irrigated soil and the growth has become rank. 



Recently Dunstan c has shown that lima beans (Phaseolus lunatus), 

 which when grown wild in Mauritius yield sufficient hydrocyanic acid 

 to produce poisoning, when cultivated in Burma lose this toxicit}^ 

 almost entirely, although it may return most unexpectedly * He was 

 unable, however, to determine the condition which increased its 

 poisonous properties. 



It is interesting to note, besides this production of hydrocyanic acid 

 from complex glucosids, that proteids, when subjected to oxidation 



« Maiden, J. H. Useful Australian Plants. Department of Agriculture New 

 South Wales, Misc. Pub. No. 22, 1896. 



& Annual Keport of the Commissioner of Agriculture, 1878, p. 168. 



cDunstan, W. R. Phaseolus Lunatus. Agricultural Ledger, 1905, No. 2. 



d Church, A. H., Food-Grains of India, 1886, p. 155; Watt, George, Dictionary of 

 the Economic Products of India, vol. 6, part 1, 1892, p. 187. 



