which harbored aphids j'ielded more hydrocj'anic acid than a second one 

 without parasites. Pease has lately claimed that the deaths from John- 

 son 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 bj' 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.^ 



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

 reference to anj^ poisonous principle.- 



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

 ened with a little water and preserved with chloroform, was sent from 

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

 botanicalh' 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 h3'drocyanic 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 ammonium sulphid was 

 added to the same filtrate, and the mixture was evaporated to dr3'ness 

 on the bath. The dried residue was then taken in hydrochloric acid 

 water, and on the addition of ferric chlorid the fluid gave the charac- 

 teristic red reaction for hydrocyanic acid. The nitro-prussid, picric 

 acid, and silver nitrate reactions were all positive for hydrocj'anic 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 h3^dro- 

 cyanic acid. 



According to our California correspondent, this plant is poisonous 

 when grown on irrigated as well as on nonirrigated lands, but especial I3' 

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



Recently Dunstan'' has shown that Lima beans (Phaseolns lunafus), 

 which when grown wild in Mauritius 3'ield sufiicient h3'droc3^anic acid to 

 produce poisoning, when cultivated in Burma lose this toxicity almost 

 entirely, although it may return most unexpectedly.^ He was unable, 

 however, to determine the condition which increased its poisonous 

 properties. 



1 Maiden, J. H. Useful xiustralian Plants. Dept. Agr. New South Wales, 

 Misc. Pub. No. 22, l.S9(j. 



- Annual Report of the Commissioner of Agriculture, 1878, p. 1(18. 



■■'Dunstan, W. R. Phaseolus Lunatus. Agr. Ledger, lifO"), No. 2. 



••Church, A. H. Kood-liraius of India. 188(), p. 155. 

 Watt, (.leorge. Dictionary of the Economic i'rodncts of India, vol. (1, ])art 1, 

 1892, p. 187. 



