ACETIC ACID. 



323 



Ustilago Panici mUiacei behaves like Ustilago crameri. 



Urocystes CejmliB, Frost (onion smut). — Selby made experiments 

 to overcome this disease, and it was chiefly by formol and lime that 

 he diminished it by introducing these products in the soil at the time 

 when the onion is sown. 



TABLE LXXII. — Shoiomg the Ac ion of Formol and Lime and Mixtures thereof 

 on Onion Rust. 



The quantity of formaline of 0375 per cent and of 0-75 per cent 

 which is used varies from 4675-6540 litres per hectare (411 gallons 

 per acre to 575-4 gallons per acre). The lime is regularly incorporated 

 with the soil ; before sowing the onions the formaline is run mechani- 

 cally on to the seeds whilst the latter are being sown by the drilling 

 machine. 



Practical Method of Disinfecting Seed=Corn. — An 88-gallon vat 

 is filled with water and about 1 quarter gallon of 40 per cent formol 

 added. Two bags containing ^ cwt. of the grain to be disinfected are 

 then placed therein. A man for fifteen minutes unceasingly turns the 

 bags HI the liquid in such a way that each bag comes in contact with 

 the formol. The sacks are raised and allowed to drain on two bars laid 

 over a low vat placed alongside the big vat. The grain is then placed 

 on the floor of a heated spot and di-ied at a temperature not above 30° 

 C. (86° F.), shovelling them until dry. By this method 4 metric tons 

 of grain may be disinfected in a day with three vats and a floor of 20 

 square metres (24 square yards). Needless to say, drying may be done 

 in the open air and in the sun when a proper space is not at disposal. 



121. Acetic Acid, CH^COHO. — Preparation. — Acetic acid results 

 from the oxidation of ethyl alcohol. The acetification of the alcohol 

 is due to its oxidation, under the influence of an aerobic ferment, 

 mycoderma accti, or mother of vinegar, and the oxygen of the air. It 

 is prepared commercially by letting wine flow slowly into casks filled 

 with wood shavings "sown" with mycoderma, and traversed from 

 below upwards by a slight current of air. The alcohol oxidizes rapidly 

 at 30° C. Acetic acid is also a product of the distillation of wood. 



Properties. — Acetic acid is a colourless liquid soluble in water and 

 alcohol, and boiling at 118° C. Vinegar, which only contains about 10 

 per cent of acatic acid, is used to preserve fruit. ^ 



1 Translator's Note. — The author here refers no doubt to the wine vinegar of 

 France ; the percentage in British mait vinegar is often less than half that given here. 



