It is thus used for extracting from the cake of fruits and seeds the oil remaining in them after they have been submitted to pressure. The sulphide is subsequently separated from the oil by distillation. In Algiers it is used for obtaining the essential oils contained in the rose, jessamine, and lavender. It is also employed for dissolving the fat from bones, and from the crude wool. Furthermore, it is an excellent solvent for caoutchouc, as well as for the ordinary resins.
Its vapour is employed by agriculturists to kill the larvæ infesting grain. Latterly, it has been employed as a disinfectant.
a. Carbon Bisulphide as an Antiseptic. By P. Zöller (‘Deut. Chem. Ges. Berl.,’ ix, 1080-1084). The author has continued his experiments on this subject with the object of determining (1) the minimum quantity of bisulphide required, and (2) whether articles of food preserved by means of it are fit for human consumption.
As regards the first point, he found that meat of all kinds, and even entire animals, in quantities up to 20 kilograms, kept perfectly well for several weeks in vessels of sheet zinc, into which 5 grams of carbon bisulphide had been introduced, the meat being either simply hung on hooks or wrapped in cloths and laid on perforated shelves in the vessels. Probably a smaller quantity of the bisulphide would suffice. Meat also kept well for 62 days in a vessel in which carbon bisulphide was liberated by introducing potassium xanthate and dilute sulphuric acid. Freshly baked bread, vegetables, and fruits of all kinds (asparagus, radishes, young beans, cucumbers, strawberries, raspberries, currants, cherries, peaches, apricots, lemons, &c.), and juices of fruits kept perfectly well in glass vessels, into which carbon bisulphide has been introduced,
in the proportion of 5-10 drops for each litre of capacity.
Bread, vegetables, and fruit thus preserved are fit to eat after simple exposure to the air, and cannot be distinguished by taste or other qualities (except a slight loss of colour in some fruits) from fresh bread, &c. Meat retains even after exposure to air the disagreeable odour of carbon bisulphide. But besides this odour, which disappears on boiling or roasting, the meat has a slight smell of the volatile fatty acids and the taste of game. To most people, however, this taste is not unpleasant. The presence of fatty acids is to be attributed to decomposition taking place in the interior of the meat, and not preventable by the carbon bisulphide, the function of which is merely to kill germs present in the air or on the surface of substances submitted to its influence.
b. By Hugo Schiff (‘Deut. Chem. Ges. Ber.,’ ix, 828). Cocoons of silkworms which had been killed by exposure to the vapours of carbon disulphide underwent no change during six months’ keeping in flasks in the laboratory. The bodies of some pigs which had been used for physiological experiments were put into a stoppered vessel with a few c. c. of carbon disulphide in 1869, and have been perfectly preserved without decomposition. The same result was obtained with a lizard 35-45 centimetres long, which had been suffocated accidentally in 1869, and was bottled whole. In this case a small quantity of liquid collected at the bottom of the vessel, and the green hue of the skin became a dirty greyish green, but not the slightest putrefaction occurred. Similar results were obtained with the intestines of poultry immersed in water in 1872 with a little carbon disulphide, in a bottle with a greased stopper; with a lump of beef weighing 200 grams; and with the body of a finch killed with paraconine. The beef yielded a normal flesh fluid, and was eaten by a dog without hesitation even after several months.
Purification.—1. It is stated that the odour of sulphide of carbon can be readily removed by allowing it to stand over mercury or corrosive sublimate for some time, and then redistilling.
2. The following method by Kern is stated by him to be the best for purifying sulphide of carbon:—The impure product is well mixed in a tall glass vessel with some lead nitrate, and with a small quantity of metallic lead. When the salt turns dark the liquid is poured into another vessel with a fresh quantity of the lead salt; and so on until the salt remains nearly white while mixed with the liquor. The sulphide of carbon is then placed in a retort, and distilled over into a well-cooled receiver.
3. M. Yvon proposes a process which consists in adding copper turnings to the sulphide; no slaking is necessary. The sulphide soon becomes nearly colourless, and loses its usually unpleasant odour. Miller says reduced copper produces the same result.