NOTES AND ABSTRACTS. 



185 



The response is not the same with all kinds of poison, but is mani- 

 fested by either a decreased rate of elongation, or by swelling, or by 

 diageotropism (sometimes by all three). 



Tobacco smoke is very injurious to seedlings of some Leguminosae 

 and Cucurbitaceae, also to many micro-organisms. It produces chemo- 

 tactic movements of leaves in certain species of Boehmeria and Split- 

 gerbera ; in some species of Boehmeria, Goldfussia, Salix, Sambucus, 

 and Potato sprouts diseased protuberances are formed. In twenty-four 

 to forty-eight hours of tobacco smoke the leaves of Mimosa pudica, 

 Caragana, Robinia, and Halimodendron fall off. Many Ferns and 

 Liverworts were severely or slightly injured in the greenhouse in conse- 

 quence of an attempt to destroy the insects by burning tobacco stems. 



The authors suggest that this method should be summarily 

 abolished. If the insecticide is nicotine, why not volatilize nicotine 

 from an extract ? If it is carbon monoxide, why not generate it 

 chemically ? {Note by abstractor. — ^This gas is excessively dangerous.) 

 The heating furnace should not be in more or less open connexion 

 with the greenhouses, for the extremely poisonous ethylene and dry 

 distillation gases are liable to escape. In cigarette smoke of cellulose 

 paper, carbon dioxide, carbon monoxide, acetylene, ethylene, methane, 

 and some higher homologues of the last three gases are present. When 

 the carbon dioxide is washed out, the smoke is still as poisonous as 

 before. Carbon monoxide at '015 concentration produces the toxic 

 effects observed. Ethylene is particularly injurious : i part in 

 10,000,000 stops elongation of the pea epicotyl, and 4 parts in 10,000,000 

 of atmosphere produces all the effects observed. 



Neither hydrogen sulphide, ammonia, nicotine, hydroc37anic 

 acid, nor pyridine, which are all present in tobacco smoke, produces the 

 effect on the seedling observed when this substance is used! Methane 

 is not certainly toxic. Acetylene and propylene are not important 

 as poisonous constituents of it. 



The etiolated epicotyl of the pea is extremely sensitive to poisonous 

 gases ; the open flower of Carnations is also exceedingly so. One 

 part of ethylene in 2,000,000 of atmosphere puts the open flower to 

 sleep in twelve hours. 



Both as regards smoke and illuminating gas, it is the heavy hydro- 

 carbons, especially ethylene, which are most dangerous. Injuries 

 from coal smoke are usually ascribed to tars and oxides of sulphur, 

 but small quantities of these heavy hydrocarbons exist in it, and 

 though they cannot be detected by ordinary methods of gas analysis, 

 they should not be neglected. Smoke from the beehive coke oven 

 is probably especially dangerous. 



Artificial illuminating gas often causes great loss, particularly during 

 cold periods (through faulty mains), and especially injures shade 

 trees. — G. F. S. E. 



Soil Disease, Observations on a Peculiar. By W. E. CoUinge 

 (Jour, Bd. Agr. vol. xx. No. 10, pp 875-879). — ^The disease 

 described is one which has troubled farmers in Warwickshire and. 



